Psychiatry Research 215 (2014) 641–645
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Psychotic-like experiences and their relationship to suicidal ideation in adolescents Joon Hwan Jang a, Yu Jin Lee a, Seong-Jin Cho b, In Hee Cho c, Na Young Shin d, Seog Ju Kim a,e,n a
Department of Psychiatry, Seoul National University Hospital, Seoul, Republic of Korea Department of Psychiatry, Gachon University of Medicine and Science, Incheon, Republic of Korea c Imom Neuropsychiatric Clinic, Seongnam, Republic of Korea d Clinical Cognitive Neuroscience Center, Neuroscience Institute, SNU-MRC, Seoul, Republic of Korea e Department of Medicine, Seoul National University College of Medicine, 28, Yeongeon-dong, Jongno-gu, Seoul, Republic of Korea b
art ic l e i nf o
a b s t r a c t
Article history: Received 29 April 2013 Received in revised form 25 December 2013 Accepted 29 December 2013 Available online 7 January 2014
Studies have suggested that psychotic-like experiences (PLEs) are associated with behavioral problems in adolescents. The aim of this study was to investigate relationships between domains of PLEs, suicidal ideation, and depression in a large community sample of adolescents. The sample consisted of 8096 Korean subjects (3184 boys and 4912 girls) aged 14 to 19 years. The level of PLEs, depression, and suicidal ideation were assessed by the Eppendorf schizophrenia inventory (ESI), Beck0 s depression inventory, and Beck0 s scale for suicidal ideation, respectively. Both the level of depression and suicidal ideation were significantly associated with PLEs. Among the four domains of the ESI, the deviant perception, ideas of reference, and auditory uncertainty were associated with the suicidal ideation. Additionally, subjects with more PLEs had significantly more suicidal ideation and depressive symptoms. PLEs in adolescents are associated with potential risk of suicide and depressive symptoms significantly mediated the association between suicidal ideation and PLEs. The presence of perceptual disturbances, ideas of reference, and depression may be regarded as warning signs for suicide-related behaviors. & 2014 Elsevier Ireland Ltd. All rights reserved.
Keywords: Psychotic-like experiences Suicide Eppendorf schizophrenia inventory Adolescents
1. Introduction Suicide is the one of the most important health issues for adolescence worldwide (Xing et al., 2010; Thompson and Light, 2011). Suicide is the leading cause of death among both adolescents and early adults in Korea (Kwon et al., 2009). The risk of suicide is reportedly significantly higher for subjects with psychotic disorders, such as schizophrenia or bipolar disorder compared with those without psychotic disorders (Hahn et al., 2002; Bertelsen et al., 2007; Lee and Kwon, 2009), and the risk is even more pronounced during the early phase of the disorders (Harvey et al., 2008). Psychotic-like experiences (PLEs) refer to sub-threshold psychotic symptoms including subclinical hallucinatory and delusional experiences and perceptual disturbances. PLEs are not rare phenomena in the general population. Studies have reported various prevalence rates of PLEs in the general population from 7% to 18% depending on the screening instruments used (Bijl et al., 1998; Scott et al., 2006; van Os et al., 2009; Nishida et al., 2010; Kelleher et al., 2012a). Nonspecific symptoms, including sleep disturbances,
n
Corresponding author. Tel.: þ 82 2 740 8418; fax: þ82 2 744 7241. E-mail address: [email protected] (S.J. Kim).
0165-1781/$ - see front matter & 2014 Elsevier Ireland Ltd. All rights reserved. http://dx.doi.org/10.1016/j.psychres.2013.12.046
depression, anxiety, concentration difficulties, and substance abuse, are also frequently present with PLEs (Hahn et al., 2002; Johns et al., 2004; Nishida et al., 2008; Scott et al., 2008). In many cases, the prodromal or high-risk states for psychosis start in adolescence, and subjects with intense and frequent PLEs were found to have a greater probability of subsequent diagnosis of psychotic disorders (Poulton et al., 2000; Hanssen et al., 2003). Identification of individuals with PLEs and investigation of their characteristics has become an important research topic in the field of adolescent psychiatry. Such studies would also probably ensure more timely, effective, and preventive interventions for a first psychotic episode and subsequent impaired quality of life (Song et al., 2011). There have been studies which have found that negative symptoms (Yung et al., 2006) and attenuated psychotic symptoms, including suspicious ideas, perceptual disturbances, and conceptual disorganization (Klosterkötter et al., 2001; Haroun et al., 2006), were associated with an increased risk of developing severe mental disorders. In the study by Yung et al. (2009) involving a community sample of high school students, bizarre experiences, persecutory ideas, and perceptual abnormalities were strongly associated with depression and poor functioning. A recent brain imaging study, on the other hand, showed reduced activity in the prefrontal cortex and anterior cingulate, regions showing alteration in subjects
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suffering from depression, in adolescents with PLEs (Jacobson et al., 2010). To date, several studies have investigated the association between PLEs and suicidal ideation/behavior during adolescence. The study by Nishida et al. (2010) reported an association between the presence of hallucinatory and delusional experiences and suicidal problems in Japanese adolescents aged 12–15 years. Kelleher et al. (2012b) also demonstrated psychotic symptoms index greatly increased risk for suicidal behavior in adolescents aged 11 to 15 years. A recent study of 1112 adolescents (Kelleher et al., 2013) found that the presence of psychotic symptoms predicted a high risk of suicidal attempts during the following 12 months. They also suggested that nonpsychotic symptoms such as depression may be partial mechanisms that mediate relationship between suicidality and PLEs. Studies that elucidate the association among PLEs, depression, and suicidal ideation would shed light on the mechanisms of how PLEs lead to behavioral problems. The current study was aimed to explore the association between PLEs and suicidal risk, and further examined an influence of depression on the relationship between these two variables in a large community-based adolescent sample aged 14–19 years. Moreover, we investigated which particular domains of PLE were related to suicidal ideation using the Eppendorf schizophrenia inventory (ESI) (Mass et al., 2000), which sensitively identifies various domains including cognitive, linguistic, sensory, and body misperception domains.
2. Methods 2.1. Participants A total of 8096 middle school and high school students (3184 boys and 4912 girls) from three different areas of the Republic of Korea participated and completed self-report questionnaires in the current study. The middle school sample (n ¼1658, grades 7–9) was recruited from five schools. The high school sample (n ¼6438, grades 10–11) was recruited from 18 schools. Six were boys0 schools, eight were girls0 schools, and nine were coeducational schools. In the participating schools, the teachers were instructed on the guidelines for distribution and collection of questionnaires. The teachers then distributed the questionnaires. All 8530 students (3431 boys and 5099 girls) registered in the selected grade of the selected school were requested to fulfill the questionnaires. Among them, 434 students (5.1%) did not complete the questionnaires and were excluded. The participants received a clear explanation that this study was conducted voluntarily and anonymously and that strict confidentiality would be maintained. Among subjects who completed self-report questionnaires, 1119 were excluded from the analysis because of a score of 0 or 1 on the ESI Frankness (FR) subscale, which indicates a tendency toward socially desirable answers. The remaining 6977 students included 2593 boys (37.2%) and 4384 girls (62.8%) who ranged in age from 14 to 19 years (mean age7 S.D., 16.8 7 1.1 years). This study was approved by the Institutional Review Board of Gachon University of Medicine and Science.
high test-retest reliability for the total score (r¼ 0.71) in Korean community adolescents (Chung et al., 2013). The severity of conscious suicidal intent was measured by the Korean version of Beck0 s 19-item Scale for Suicidal Ideation (SSI; range 0–38) (Beck et al., 1979; Lee and Kwon, 2009), which has been shown to have a significant correlation with suicide-attempt history in Korean university students (r ¼0.36; Lee and Kwon, 2009) and in psychiatric outpatients (r ¼0.50; Beck et al., 1997). The levels of depressive symptoms were measured by the Korean version of the Beck depression inventory (BDI; range 0–63) (Beck et al., 1961; Hahn et al., 2002). All measures were self-administered. When adolescents were classified as having high clinical risk (ESI Z 29 or BDIZ 16), results were notified to their parents and further psychiatric evaluation was recommended.
2.3. Statistical analysis Data analysis was conducted using PASW Statistics 18.0 for Windows (SPSS, Inc., Chicago, IL, USA). All the raw data of the clinical scales were square-root transformed to more closely approximate a normal distribution. Normal distribution was measured by skewness and kurtosis coefficients and visual inspection of plots. Cook0 s distance greater than 1 was used to detect possible outliers, and no outlier was identified. Pearson correlation was used to examine the relationship among various clinical variables. To examine the indirect effect of depression on relations between subjective PLEs and suicidal ideation, multiple regression analyses following Baron and Kenny0 s recommendation (Baron and Kenny, 1986) were conducted after controlling for age and gender, and the Sobel test (Preacher and Hayes, 2004) was performed to test all relevant regressions in a single analysis. Based on the Baron and Kenny0 s model, the following conditions must be satisfied to support a mediation effect: (1) the independent variable (PLEs) must significantly affect mediator (depression), (2) the independent variable should be associated with the dependent variable (suicidal ideation), and (3) the mediator must significantly explain the dependent variable in the multiple regression equation, with a reduced effect of the independent variable on the dependent variable. For the presence of psychosis proneness, subjects were coded into two groups according the ESI cutoff score (29) (Chung et al., 2013). We divided subjects with a greater intensity of PLEs according to the level of depressive symptoms and compared the SSI score between subjects with low and high depressive symptoms. Additionally, to examine an effect of PLEs on suicidal attempt in subjects with depression, we compared the SSI scores between subjects with high level of depressive symptoms which had low and high ESI scores. The cutoff score of depression (16) was set on a basis of a previous validity study (Shin et al., 1993). The Student0 s t-test and the chi-square test were used for group comparison of the means and the frequencies of demographic data. Analysis of covariance (ANCOVA) was used to compare between groups while controlling demographic variables that significantly differed between groups. A p-value of o 0.05 was considered statistically significant.
3. Results 3.1. Demographical and clinical data The demographic and clinical characteristics of the subjects are presented in Tables 1 and 2. The SSI score was significantly associated with both the BDI (r¼0.65, po0.0001) and the ESI scores (r¼0.43, Table 1 Demographic and clinical characteristics of the participants (n¼ 6977).
2.2. Materials The prevalence of subjective PLE was assessed by the ESI (range 0–102) (Mass, 2000). The ESI is a reliable self-report instrument that measures self-experienced disturbances found in both subjects at risk for psychosis and schizophrenic patients. The ESI comprises 40 items, 34 of which are combined to assess the four domains of PLE symptoms: (1) attention and speech impairment (AS: impairments of the adequate reception and interpretation of environmental stimuli, above all affecting speech); (2) ideas of reference (IR: tendency to interpret trivial events in an excessively meaningful way); (3) auditory uncertainty (AU: inability to discriminate between thoughts and words which have been heard); and (4) deviant perception (DP: alterations of perceptual processes including disturbances of the body image). Moreover, the ESI contains a five-item FR scale that evaluates the tendency to answer questions in a socially desirable manner and one item assessing general survey motivation. The ESI items are answered using a fourpoint Likert scale from 0 (“strongly disagree”) to 3 (“strongly agree”), which are summarized in the subscale scores. The Korean version of ESI has good internal consistencies for the total score and four domains (Cronbach0 s α, 0.70–0.92) and
Raw score
Transformed score
Male % Age (yr) SSI BDI ESI
37.2 16.8 71.1 7.4 7 5.4 10.7 76.9
2.5 71.0a 3.17 1.1a
Total AS AU DP IR
10.3 79.9 4.0 7 3.5 1.9 7 2.4 1.7 7 2.5 2.8 7 5.4
2.9 71.5a 1.8 7 1.0a 1.0 7 0.9a 0.9 70.9a 1.4 7 0.9a
Abbreviations: SSI, scale for suicide ideation; BDI, Beck depression inventory; ESI, Eppendorf schizophrenia inventory; AS, attention and speech impairment; AU, auditory uncertainty; DP, deviant perception; IR, ideas of reference. a
Square-root transformation.
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Table 2 Correlations among clinical variables in a whole sample.
SSI BDI
BDI
ESI total
AS
AU
DP
IR
0.65nn –
0.43nn 0.55nn
0.35nn 0.49nn
0.35nn 0.042nn
0.36nn 0.042nn
0.39nn 0.48nn
Abbreviations: SSI, scale for suicide ideation; Beck depression inventory; ESI, Eppendorf schizophrenia inventory; AS, attention and speech impairment; AU, auditory uncertainty; DP, deviant perception; IR, ideas of reference. nn
p o0.0001.
Table 3 Summary for the analyses of variables in the path model. 2
B
β
t
Regression of BDI or SSI on ESI Step I: BDI 0.32 Step II: SSI 0.22
0.41 0.32
0.56 0.44
56.39nn 41.78nn
Multiple regression on SSI Step III BDI 0.44 ESI
0.55 0.09
0.56 0.13
51.63nn 11.81nn
R
Abbreviations: BDI, Beck depression inventory; ESI, Eppendorf schizophrenia inventory; SSI, scale for suicide ideation. nn
p o0.0001.
po0.0001). The ESI score was significantly related to the BDI score (r¼ 0.55, po0.0001).
Fig. 1. The direct model represents the results of simple regression analysis. The mediated model represents relationship between PLEs and suicidal ideation as mediated by depressive symptoms. Values on paths are standardized Beta coefficients.nnp o 0.0001. Abbreviation: PLEs, psychotic-like experiences.
Table 4 Comparison of suicidal ideation between high clinical risk subjects for psychotic proneness with low and high depression.
Sex (male %) Age SSIa SSIb
Low depression (n¼ 121)
High depression (n¼ 279)
Statistics d.f.
p
55.4 17.0 (0.8) 2.8 (0.9) 9.01 (5.4)
41.2 16.8 (1.1) 4.0 (0.9) 16.6 (6.9)
χ2 ¼ 6.82 1 0.01 t ¼ 2.16 297.5 0.03 F ¼20.75 1,396 o 0.001
Data are presented as mean (S.D.). Abbreviation: SSI, scale for suicide ideation. a b
Square-root transformation. Raw score.
3.2. Analysis of the mediation model Table 3 summarizes the regression analyses through the three steps to examine an effect of depressive symptoms on the relation between suicidal ideation and PLEs. In the first step, PLEs were significantly associated with depressive symptoms (F3,6973 ¼1104.03, po0.0001). In the second step, the PLEs were found to significantly affect suicidal ideation (F3,6973 ¼655.33, po0.0001). Finally, in the multiple regression equation, the depressive symptoms were found to be significantly related to the suicidal ideation, and the effect of PLEs on suicidal ideation was significant but considerably reduced (F3,6972 ¼1345.86, po0.0001). Additionally, the results of Sobel0 s test indicated that an indirect effect was significant for the SSI (Z¼ 38.00, po0.0001). Fig. 1 illustrates relationship between PLEs and suicidal ideation. When the four subscale scores were put into the model, all four subscores were significantly associated with the depressive symptom (F6,6970 ¼547.15, po0.0001) and the suicidal ideation (F6,6970 ¼327.27, po0.0001). In the multiple regression equation, the depressive symptom was found to be significantly related to the suicidal ideation, and the effect of the AS was not significant and those of the rest scales were reduced (F7,6969 ¼777.52, po0.0001). 3.3. Associations among suicidal ideation, level of PLEs and depression The sample was classified into two groups based on the cutoff score of the ESI: those with a greater intensity of PLEs (total ESI scoreZ29, n ¼400) vs. those with a lesser intensity of PLEs (total ESI scoreo29, n ¼ 6577). There was a significantly higher percentage of boys (45.5% vs. 36.7%; χ2 ¼ 12.62, p ¼0.001) in the greater PLEs group than in the lesser PLEs group, but there was no significant difference in age between the two groups (16.8 vs. 16.8; t¼ 1.26, d.f. ¼454, p ¼0.21). ANCOVA revealed that the subjects with a greater intensity of PLEs had significantly more
Table 5 Comparison of suicidal ideation between depressive subjects with low and high PLEs.
Sex (male %) Age SSIa SSIb
Low PLEs (n¼ 1108)
High PLEs (n¼ 279)
Statistics
d.f.
p
27.3 16.8 (1.0) 3.5 (0.8) 12.8 (5.6)
41.2 16.8 (1.1) 4.0 (0.9) 16.6 (6.9)
χ2 ¼20.3 1 o 0.001 t¼ 0.49 407 0.62 F¼ 101.32 1,1384 o 0.001
Data are presented as mean (S.D.). Abbreviation: PLEs, psychotic-like experiences; SSI, scale for suicide ideation. a b
Square-root transformation. Raw score.
suicidal ideation (SSI raw score: 14.3 vs. 6.9; F1,6974 ¼ 580.70, po 0.0001) and depressive symptoms (BDI raw score: 21.3 vs. 10.0; F1,6974 ¼ 843.71, p o0.0001) than those with a lesser intensity of PLEs. In addition, the subjects with a greater intensity of PLEs were divided into two groups with low (n ¼121) and high (n ¼ 279) depressive symptoms according to the BDI cutoff score (total BDI score Z16). Analysis yielded significantly lower percentage of boys (χ2 ¼ 6.82, d.f. ¼1, p¼ 0.01) and younger subjects (t ¼2.16, d.f. ¼298, po 0.05) in the high depression group than in the low depression group (Table 4). Therefore gender and age variables were controlled in the subsequent analysis. The ANCOVA analysis showed that the subjects with high depressive symptoms had significantly higher SSI scores than those with low depressive symptoms after controlling for gender and age (F (1,396) ¼ 120.75, po 0.001).
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When the SSI scores were compared between the subjects with high level of depressive symptoms who had high (n ¼279) and low ESI total scores (n ¼1108), the subjects with depression who had high ESI score showed significantly higher SSI score than did those with depression who had low ESI score (F (1,1384) ¼101.32, p o0.001), while controlling gender (Table 5).
4. Discussion Our results indicate that PLEs in the early developmental stage are associated with suicidal ideation independent of gender or depressive symptoms. The association between suicidal ideation and PLEs was mediated by depressive symptoms. We also found that intense PLE symptoms are an independent risk factor for suicidal ideation among teenagers. Additionally, DP, IR, and AU were associated with suicidality. To our knowledge, the current study is the largest community-based study to investigate associations between PLEs and the presence of suicidal ideation in adolescents. In this study, PLE was a predictor of high suicidal ideation. Additionally, the level of suicidal ideation was positively associated with the degree of PLEs in adolescents. Teenagers with a greater intensity of PLEs had twice as many SSI scores as did individuals with lesser PLEs. Population-based studies have reported that PLEs are common phenomena in the general population, especially among teenagers (Hanssen et al., 2005; Scott et al., 2006, 2008). The high prevalence of PLEs among adolescents could be explained by exposure to unusual or culturally incongruent ideas that are frequently observed during adolescence (Scott et al., 2006) or abnormal pruning of the brain, mostly in the prefrontal cortex, in late adolescence. Recently, Nishida et al. (2010) reported that 34% of subjects with suicidal ideation experienced PLEs. These results suggest that the experience of PLEs during adolescence may independently predict increased suicidal risk. Furthermore, PLEs in this period are associated with later psychotic disorders and behavioral problems (Poulton et al., 2000; Scott et al., 2008; Kinoshita et al., 2011). The risk of suicide is known to be significantly higher in both individuals at ultra-high-risk for psychosis (Hutton et al., 2011) and patients with psychosis (Palmer et al., 2005; Bertelsen et al., 2007) that warrant early detection and intervention targeting PLEs. This is the first study demonstrating the mediating role of depressive symptoms on the effect of PLEs on suicidal ideation. A recent study investigating associations between PLEs and suicidal risk found that very few of the subjects reported commanding hallucinations to harm or kill themselves (Kelleher et al., 2012b). It could be suggested that PLEs may impact suicidal ideation via indirect mechanisms. Previous studies have reported association between PLEs and symptoms of depression in adolescents (Dhossche et al., 2002; Nishida et al., 2008). Functional and structural neuroimaging studies have emphasized abnormalities in the medial prefrontal cortex and anterior cingulate, that play important roles in emotional regulation, modulation of emotional responses and conflict monitoring, in both individuals with attenuated psychotic symptoms and with depression (Jacobson et al., 2010; Shim et al., 2010; Yoshimura et al., 2010). The adolescents with PLEs may be more sensitive to environmental noises (Nishida et al., 2008). Therefore, the depressive symptoms in adolescents with PLEs could aggravate distortion of sense of reality in social situations, and this distortion may be linked to suicidal ideation. Studies also have suggested increased affective reactivity as well as poorer coping skills to stressful life events in subjects with PLEs as risk factors for suicidal behaviors (Lataster et al., 2009; Lin et al., 2011). However, future work will
be warranted to investigate biological underpinnings of suicidal behaviors. The present research sample of mid- to late teenagers (14–19 years of age) was, as far as we know, the largest ever examined in this type of study. In many cases, the first psychotic episode occurs around the age of 20 years. Therefore, early detection should start in mid- to late adolescence, ages that were included in the present study. This could be regarded as a strength of this study from a clinical perspective compared with the previous studies, which included subjects in their early teens. Subclinical psychotic symptoms and signs are more likely to be overlooked than depression (Houston et al., 2001; Nishida et al., 2010). Clinicians should focus on the presence of both PLEs and depressive symptoms in adolescents. The current study is also the first to reveal that perceptual/ cognitive domains (i.e., DP and AU) as well as thought-content disturbances (i.e., IR) of ESI are related to high suicidality. The present results indicate that each PLE domain could independently predict suicidal ideation. The DP and AU subscales refer to aberrations in perceptual processes, especially those involving disturbances of self-image and discrimination between thoughts and words that have actually been heard, respectively. The IR subscale represents a tendency to interpret ordinary events in excessively meaningful or delusional ways. These subscales are regarded as indicators of psychotic exacerbations (Mass et al., 2005). Our results suggest that the presence of perceptual disturbances and referential ideas in adolescents could be regarded as a warning sign for suicide-related behaviors. There are several limitations of this study. First, we used selfreport questionnaires and could not found the prevalence of frank psychosis. Screening via self-reports has a potential to overestimate the actual risk for subsequent psychosis compared with the interview-based surveys (Kendler et al., 1996). Moreover, the possibility that some portion of participants were having psychosis, such as schizophrenia or major depressive disorder with psychotic symptoms, could not be excluded. However, face-toface interviews are impractical for large-scale population-based studies like this one. Second, as a result of the cross-sectional nature of this study, information about longitudinal causal direction was not available. A longitudinal study might be warranted to evaluate subsequent suicidal behaviors and transition to psychosis in young individuals with PLEs. Another area of concern involves the sample representativeness, as female or high school students were majority of our participants. To investigate the true prevalence of PLEs in Korea, future study with more representative sample should be needed. Last, because of the large sample size of this study, relatively small associations between clinical variables could be shown statistically significant. In conclusion, we found that PLE among adolescents was a predictor of suicidal ideation, mediated by depressive symptoms. Our study emphasizes the necessity of early detection and intervention for adolescents with PLEs. Therefore, future longitudinal studies are warranted to focus on early intervention and prevention of subclinical psychotic symptoms and depressive symptoms in adolescents.
References Baron, R.M., Kenny, D.A., 1986. The moderator-mediator variable distinction in social psychological research: conceptual, strategic, and statistical considerations. Journal of Personality and Social Psychology 51, 1173–1182. Beck, A.T., Brown, G.K., Steer, R.A., 1997. Psychometric characteristics of the Scale for Suicide Ideation with psychiatric outpatients. Behaviour Research and Therapy 35, 1039–1046. Beck, A.T., Kovacs, M., Weissman, A., 1979. Assessment of suicidal intention: the Scale for Suicide Ideation. Journal of Consulting and Clinical Psychology 47, 343–352.
J.H. Jang et al. / Psychiatry Research 215 (2014) 641–645
Beck, A.T., Ward, C.H., Mendelson, M., Mock, J., Erbaugh, J., 1961. An inventory for measuring depression. Archives of General Psychiatry 4, 561–571. Bertelsen, M., Jeppesen, P., Petersen, L., Thorup, A., Ohlenschlaeger, J., le Quach, P., Christensen, T.O., Krarup, G., Jorgensen, P., Nordentoft, M., 2007. Suicidal behaviour and mortality in first-episode psychosis: the OPUS trial. The British Journal of Psychiatry Supplement 51, s140–146. Bijl, R.V., van Zessen, G., Ravelli, A., de Rijk, C., Langendoen, Y., 1998. The Netherlands Mental Health Survey and Incidence Study (NEMESIS): objectives and design. Social Psychiatry and Psychiatric Epidemiology 33, 581–586. Chung, Y.C., Kang, N.I., Im, Y.J., Kim, S.W., Cho, I.H., Lee, Y.M., Kwon, J.S., 2013. Validation of the Korean version of the Eppendorf Schizophrenia Inventory as a screening measure to detect adolescents at ultra-high risk for psychosis. Early Intervention in Psychiatry 7, 71–79. Dhossche, D., Ferdinand, R., Van der Ende, J., Hofstra, M.B., Verhulst, F., 2002. Diagnostic outcome of self-reported hallucinations in a community sample of adolescents. Psychological Medicine 32, 619–627. Hahn, H.M., Yum, T.H., Shin, Y.W., Kim, K.H., Yoon, D.J., Chung, K.J., 2002. A standardization study of Beck Depression Inventory in Korea. Journal of Korean Neuropsychiatric Association 41, 487–502. Hanssen, M., Bak, M., Bijl, R., Vollebergh, W., van Os, J., 2005. The incidence and outcome of subclinical psychotic experiences in the general population. The British Journal of Clinical Psychology 44, 181–191. Hanssen, M.S., Bijl, R.V., Vollebergh, W., van Os, J., 2003. Self-reported psychotic experiences in the general population: a valid screening tool for DSM-III-R psychotic disorders? Acta Psychiatrica Scandinavica 107, 369–377. Haroun, N., Dunn, L., Haroun, A., Cadenhead, K.S., 2006. Risk and protection in prodromal schizophrenia: ethical implications for clinical practice and future research. Schizophrenia Bulletin 32, 166–178. Harvey, S.B., Dean, K., Morgan, C., Walsh, E., Demjaha, A., Dazzan, P., Morgan, K., Lloyd, T., Fearon, P., Jones, P.B., Murray, R.M., 2008. Self-harm in first-episode psychosis. The British Journal of Psychiatry 192, 178–184. Houston, K., Hawton, K., Shepperd, R., 2001. Suicide in young people aged 15-24: a psychological autopsy study. Journal of Affective Disorders 63, 159–170. Hutton, P., Bowe, S., Parker, S., Ford, S., 2011. Prevalence of suicide risk factors in people at ultra-high risk of developing psychosis: a service audit. Early Intervention in Psychiatry 5, 375–380. Jacobson, S., Kelleher, I., Harley, M., Murtagh, A., Clarke, M., Blanchard, M., Connolly, C., O’Hanlon, E., Garavan, H., Cannon, M., 2010. Structural and functional brain correlates of subclinical psychotic symptoms in 11–13 year old schoolchildren. NeuroImage 49, 1875–1885. Johns, L.C., Cannon, M., Singleton, N., Murray, R.M., Farrell, M., Brugha, T., Bebbington, P., Jenkins, R., Meltzer, H., 2004. Prevalence and correlates of self-reported psychotic symptoms in the British population. The British Journal of Psychiatry 185, 298–305. Kelleher, I., Connor, D., Clarke, M.C., Devlin, N., Harley, M., Cannon, M., 2012a. Prevalence of psychotic symptoms in childhood and adolescence: a systematic review and meta-analysis of population-based studies. Psychological Medicine 42, 1857–1864. Kelleher, I., Lynch, F., Harley, M., Molloy, C., Roddy, S., Fitzpatrick, C., Cannon, M., 2012b. Psychotic symptoms in adolescence index risk for suicidal behavior: findings from 2 population-based case-control clinical interview studies. Archives of General Psychiatry 69, 1277–1283. Kelleher, I., Corcoran, P., Keeley, H., Wigman, J.T., Devlin, N., Ramsay, H., Wasserman, C., Carli, V., Sarchiapone, M., Hoven, C., Wasserman, D., Cannon, M., 2013. Psychotic symptoms and population risk for suicide attempt: a prospective cohort study. JAMA Psychiatry 70, 940–948. Kendler, K.S., Gallagher, T.J., Abelson, J.M., Kessler, R.C., 1996. Lifetime prevalence, demographic risk factors, and diagnostic validity of nonaffective psychosis as assessed in a US community sample. the National Comorbidity Survey. Archives of General Psychiatry 53, 1022–1031. Kinoshita, Y., Shimodera, S., Nishida, A., Kinoshita, K., Watanabe, N., Oshima, N., Akechi, T., Sasaki, T., Inoue, S., Furukawa, T.A., Okazaki, Y., 2011. Psychotic-like experiences are associated with violent behavior in adolescents. Schizophrenia Research 126, 245–251. Klosterkötter, J., Hellmich, M., Steinmeyer, E.M., Schultze-Lutter, F., 2001. Diagnosing schizophrenia in the initial prodromal phase. Archives of General Psychiatry 58, 158–164. Kwon, J.W., Chun, H., Cho, S.I., 2009. A closer look at the increase in suicide rates in South Korea from 1986–2005. BMC Public Health 9, 72. Lataster, T., Wichers, M., Jacobs, N., Mengelers, R., Derom, C., Thiery, E., Van Os, J., Myin-Germeys, I., 2009. Does reactivity to stress cosegregate with subclinical
645
psychosis? A general population twin study. Acta Psychiatrica Scandinavica 119, 45–53. Lee, H.S., Kwon, J.H., 2009. Validation for the Beck Scale for Suicide Ideation with Korean university students. Korean Journal of Clinical Psychology 28, 1155–1172. Lin, A., Wigman, J.T., Nelson, B., Vollebergh, W.A., van Os, J., Baksheev, G., Ryan, J., Raaijmakers, Q.A., Thompson, A., Yung, A.R., 2011. The relationship between coping and subclinical psychotic experiences in adolescents from the general population: a longitudinal study. Psychological Medicine 41, 2535–2546. Mass, R., 2000. Characteristic subjective experiences of schizophrenia. Schizophrenia Bulletin 26, 921. Mass, R., Haasen, C., Borgart, E.J., 2005. Abnormal subjective experiences of schizophrenia: evaluation of the Eppendorf Schizophrenia Inventory. Psychiatry Research 135, 91–101. Mass, R., Haasen, C., Wolf, K., 2000. [The Eppendorf Schizophrenia Inventory (ESI). Development and evaluation of a questionnaire for assessment of characteristic self perception of cognitive dysfunctions by schizophrenic patients]. Der Nervenarzt 71, 885–892. Nishida, A., Sasaki, T., Nishimura, Y., Tanii, H., Hara, N., Inoue, K., Yamada, T., Takami, T., Shimodera, S., Itokawa, M., Asukai, N., Okazaki, Y., 2010. Psychotic-like experiences are associated with suicidal feelings and deliberate self-harm behaviors in adolescents aged 12–15 years. Acta Psychiatrica Scandinavica 121, 301–307. Nishida, A., Tanii, H., Nishimura, Y., Kajiki, N., Inoue, K., Okada, M., Sasaki, T., Okazaki, Y., 2008. Associations between psychotic-like experiences and mental health status and other psychopathologies among Japanese early teens. Schizophrenia Research 99, 125–133. Palmer, B.A., Pankratz, V.S., Bostwick, J.M., 2005. The lifetime risk of suicide in schizophrenia: a reexamination. Archives of General Psychiatry 62, 247–253. Poulton, R., Caspi, A., Moffitt, T.E., Cannon, M., Murray, R., Harrington, H., 2000. Children0 s self-reported psychotic symptoms and adult schizophreniform disorder: a 15-year longitudinal study. Archives of General Psychiatry 57, 1053–1058. Preacher, K.J., Hayes, A.F., 2004. SPSS and SAS procedures for estimating indirect effects in simple mediation models. Behavior Research Methods, Instruments, & Computers 36, 717–731. Scott, J., Chant, D., Andrews, G., McGrath, J., 2006. Psychotic-like experiences in the general community: the correlates of CIDI psychosis screen items in an Australian sample. Psychological Medicine 36, 231–238. Scott, J., Welham, J., Martin, G., Bor, W., Najman, J., O’Callaghan, M., Williams, G., Aird, R., McGrath, J., 2008. Demographic correlates of psychotic-like experiences in young Australian adults. Acta Psychiatrica Scandinavica 118, 230–237. Shim, G., Oh, J.S., Jung, W.H., Jang, J.H., Choi, C.H., Kim, E., Park, H.Y., Choi, J.S., Jung, M.H., Kwon, J.S., 2010. Altered resting-state connectivity in subjects at ultrahigh risk for psychosis: an fMRI study. Behavioral and Brain Functions 6, 58. Shin, M.S., Kim, J.S., Park, K.B., 1993. The cutoff score of the Korean version of Beck Depression Inventory. Korean Journal of Clinical Psychology 12, 71–81. Song, Y.Y., Kim, K.R., Park, J.Y., Lee, S.Y., Kang, J.I., Lee, E., An, S.K., Kwon, J.S., 2011. Associated factors of quality of life in first-episode schizophrenia patients. Psychiatry Investigation 8, 201–206. Thompson, M.P., Light, L.S., 2011. Examining gender differences in risk factors for suicide attempts made 1 and 7 years later in a nationally representative sample. The Journal of Adolescent Health 48, 391–397. van Os, J., Linscott, R.J., Myin-Germeys, I., Delespaul, P., Krabbendam, L., 2009. A systematic review and meta-analysis of the psychosis continuum: evidence for a psychosis proneness-persistence-impairment model of psychotic disorder. Psychological Medicine 39, 179–195. Xing, X.Y., Tao, F.B., Wan, Y.H., Xing, C., Qi, X.Y., Hao, J.H., Su, P.Y., Pan, H.F., Huang, L., 2010. Family factors associated with suicide attempts among Chinese adolescent students: a national cross-sectional survey. The Journal of Adolescent Health 46, 592–599. Yoshimura, S., Okamoto, Y., Onoda, K., Matsunaga, M., Ueda, K., Suzuki, S., Yamawaki, S., 2010. Rostral anterior cingulate cortex activity mediates the relationship between the depressive symptoms and the medial prefrontal cortex activity. Journal of Affective Disorders 122, 76–85. Yung, A.R., Buckby, J.A., Cotton, S.M., Cosgrave, E.M., Killackey, E.J., Stanford, C., Godfrey, K., McGorry, P.D., 2006. Psychotic-like experiences in nonpsychotic help-seekers: associations with distress, depression, and disability. Schizophrenia Bulletin 32, 352–359. Yung, A.R., Nelson, B., Baker, K., Buckby, J.A., Baksheev, G., Cosgrave, E.M., 2009. Psychotic-like experiences in a community sample of adolescents: implications for the continuum model of psychosis and prediction of schizophrenia. Australian and New Zealand Journal of Psychiatry 43, 118–128.
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Psychiatry Research journal homepage: www.elsevier.com/locate/psychres
Psychotic-like experiences and their relationship to suicidal ideation in adolescents Joon Hwan Jang a, Yu Jin Lee a, Seong-Jin Cho b, In Hee Cho c, Na Young Shin d, Seog Ju Kim a,e,n a
Department of Psychiatry, Seoul National University Hospital, Seoul, Republic of Korea Department of Psychiatry, Gachon University of Medicine and Science, Incheon, Republic of Korea c Imom Neuropsychiatric Clinic, Seongnam, Republic of Korea d Clinical Cognitive Neuroscience Center, Neuroscience Institute, SNU-MRC, Seoul, Republic of Korea e Department of Medicine, Seoul National University College of Medicine, 28, Yeongeon-dong, Jongno-gu, Seoul, Republic of Korea b
art ic l e i nf o
a b s t r a c t
Article history: Received 29 April 2013 Received in revised form 25 December 2013 Accepted 29 December 2013 Available online 7 January 2014
Studies have suggested that psychotic-like experiences (PLEs) are associated with behavioral problems in adolescents. The aim of this study was to investigate relationships between domains of PLEs, suicidal ideation, and depression in a large community sample of adolescents. The sample consisted of 8096 Korean subjects (3184 boys and 4912 girls) aged 14 to 19 years. The level of PLEs, depression, and suicidal ideation were assessed by the Eppendorf schizophrenia inventory (ESI), Beck0 s depression inventory, and Beck0 s scale for suicidal ideation, respectively. Both the level of depression and suicidal ideation were significantly associated with PLEs. Among the four domains of the ESI, the deviant perception, ideas of reference, and auditory uncertainty were associated with the suicidal ideation. Additionally, subjects with more PLEs had significantly more suicidal ideation and depressive symptoms. PLEs in adolescents are associated with potential risk of suicide and depressive symptoms significantly mediated the association between suicidal ideation and PLEs. The presence of perceptual disturbances, ideas of reference, and depression may be regarded as warning signs for suicide-related behaviors. & 2014 Elsevier Ireland Ltd. All rights reserved.
Keywords: Psychotic-like experiences Suicide Eppendorf schizophrenia inventory Adolescents
1. Introduction Suicide is the one of the most important health issues for adolescence worldwide (Xing et al., 2010; Thompson and Light, 2011). Suicide is the leading cause of death among both adolescents and early adults in Korea (Kwon et al., 2009). The risk of suicide is reportedly significantly higher for subjects with psychotic disorders, such as schizophrenia or bipolar disorder compared with those without psychotic disorders (Hahn et al., 2002; Bertelsen et al., 2007; Lee and Kwon, 2009), and the risk is even more pronounced during the early phase of the disorders (Harvey et al., 2008). Psychotic-like experiences (PLEs) refer to sub-threshold psychotic symptoms including subclinical hallucinatory and delusional experiences and perceptual disturbances. PLEs are not rare phenomena in the general population. Studies have reported various prevalence rates of PLEs in the general population from 7% to 18% depending on the screening instruments used (Bijl et al., 1998; Scott et al., 2006; van Os et al., 2009; Nishida et al., 2010; Kelleher et al., 2012a). Nonspecific symptoms, including sleep disturbances,
n
Corresponding author. Tel.: þ 82 2 740 8418; fax: þ82 2 744 7241. E-mail address: [email protected] (S.J. Kim).
0165-1781/$ - see front matter & 2014 Elsevier Ireland Ltd. All rights reserved. http://dx.doi.org/10.1016/j.psychres.2013.12.046
depression, anxiety, concentration difficulties, and substance abuse, are also frequently present with PLEs (Hahn et al., 2002; Johns et al., 2004; Nishida et al., 2008; Scott et al., 2008). In many cases, the prodromal or high-risk states for psychosis start in adolescence, and subjects with intense and frequent PLEs were found to have a greater probability of subsequent diagnosis of psychotic disorders (Poulton et al., 2000; Hanssen et al., 2003). Identification of individuals with PLEs and investigation of their characteristics has become an important research topic in the field of adolescent psychiatry. Such studies would also probably ensure more timely, effective, and preventive interventions for a first psychotic episode and subsequent impaired quality of life (Song et al., 2011). There have been studies which have found that negative symptoms (Yung et al., 2006) and attenuated psychotic symptoms, including suspicious ideas, perceptual disturbances, and conceptual disorganization (Klosterkötter et al., 2001; Haroun et al., 2006), were associated with an increased risk of developing severe mental disorders. In the study by Yung et al. (2009) involving a community sample of high school students, bizarre experiences, persecutory ideas, and perceptual abnormalities were strongly associated with depression and poor functioning. A recent brain imaging study, on the other hand, showed reduced activity in the prefrontal cortex and anterior cingulate, regions showing alteration in subjects
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suffering from depression, in adolescents with PLEs (Jacobson et al., 2010). To date, several studies have investigated the association between PLEs and suicidal ideation/behavior during adolescence. The study by Nishida et al. (2010) reported an association between the presence of hallucinatory and delusional experiences and suicidal problems in Japanese adolescents aged 12–15 years. Kelleher et al. (2012b) also demonstrated psychotic symptoms index greatly increased risk for suicidal behavior in adolescents aged 11 to 15 years. A recent study of 1112 adolescents (Kelleher et al., 2013) found that the presence of psychotic symptoms predicted a high risk of suicidal attempts during the following 12 months. They also suggested that nonpsychotic symptoms such as depression may be partial mechanisms that mediate relationship between suicidality and PLEs. Studies that elucidate the association among PLEs, depression, and suicidal ideation would shed light on the mechanisms of how PLEs lead to behavioral problems. The current study was aimed to explore the association between PLEs and suicidal risk, and further examined an influence of depression on the relationship between these two variables in a large community-based adolescent sample aged 14–19 years. Moreover, we investigated which particular domains of PLE were related to suicidal ideation using the Eppendorf schizophrenia inventory (ESI) (Mass et al., 2000), which sensitively identifies various domains including cognitive, linguistic, sensory, and body misperception domains.
2. Methods 2.1. Participants A total of 8096 middle school and high school students (3184 boys and 4912 girls) from three different areas of the Republic of Korea participated and completed self-report questionnaires in the current study. The middle school sample (n ¼1658, grades 7–9) was recruited from five schools. The high school sample (n ¼6438, grades 10–11) was recruited from 18 schools. Six were boys0 schools, eight were girls0 schools, and nine were coeducational schools. In the participating schools, the teachers were instructed on the guidelines for distribution and collection of questionnaires. The teachers then distributed the questionnaires. All 8530 students (3431 boys and 5099 girls) registered in the selected grade of the selected school were requested to fulfill the questionnaires. Among them, 434 students (5.1%) did not complete the questionnaires and were excluded. The participants received a clear explanation that this study was conducted voluntarily and anonymously and that strict confidentiality would be maintained. Among subjects who completed self-report questionnaires, 1119 were excluded from the analysis because of a score of 0 or 1 on the ESI Frankness (FR) subscale, which indicates a tendency toward socially desirable answers. The remaining 6977 students included 2593 boys (37.2%) and 4384 girls (62.8%) who ranged in age from 14 to 19 years (mean age7 S.D., 16.8 7 1.1 years). This study was approved by the Institutional Review Board of Gachon University of Medicine and Science.
high test-retest reliability for the total score (r¼ 0.71) in Korean community adolescents (Chung et al., 2013). The severity of conscious suicidal intent was measured by the Korean version of Beck0 s 19-item Scale for Suicidal Ideation (SSI; range 0–38) (Beck et al., 1979; Lee and Kwon, 2009), which has been shown to have a significant correlation with suicide-attempt history in Korean university students (r ¼0.36; Lee and Kwon, 2009) and in psychiatric outpatients (r ¼0.50; Beck et al., 1997). The levels of depressive symptoms were measured by the Korean version of the Beck depression inventory (BDI; range 0–63) (Beck et al., 1961; Hahn et al., 2002). All measures were self-administered. When adolescents were classified as having high clinical risk (ESI Z 29 or BDIZ 16), results were notified to their parents and further psychiatric evaluation was recommended.
2.3. Statistical analysis Data analysis was conducted using PASW Statistics 18.0 for Windows (SPSS, Inc., Chicago, IL, USA). All the raw data of the clinical scales were square-root transformed to more closely approximate a normal distribution. Normal distribution was measured by skewness and kurtosis coefficients and visual inspection of plots. Cook0 s distance greater than 1 was used to detect possible outliers, and no outlier was identified. Pearson correlation was used to examine the relationship among various clinical variables. To examine the indirect effect of depression on relations between subjective PLEs and suicidal ideation, multiple regression analyses following Baron and Kenny0 s recommendation (Baron and Kenny, 1986) were conducted after controlling for age and gender, and the Sobel test (Preacher and Hayes, 2004) was performed to test all relevant regressions in a single analysis. Based on the Baron and Kenny0 s model, the following conditions must be satisfied to support a mediation effect: (1) the independent variable (PLEs) must significantly affect mediator (depression), (2) the independent variable should be associated with the dependent variable (suicidal ideation), and (3) the mediator must significantly explain the dependent variable in the multiple regression equation, with a reduced effect of the independent variable on the dependent variable. For the presence of psychosis proneness, subjects were coded into two groups according the ESI cutoff score (29) (Chung et al., 2013). We divided subjects with a greater intensity of PLEs according to the level of depressive symptoms and compared the SSI score between subjects with low and high depressive symptoms. Additionally, to examine an effect of PLEs on suicidal attempt in subjects with depression, we compared the SSI scores between subjects with high level of depressive symptoms which had low and high ESI scores. The cutoff score of depression (16) was set on a basis of a previous validity study (Shin et al., 1993). The Student0 s t-test and the chi-square test were used for group comparison of the means and the frequencies of demographic data. Analysis of covariance (ANCOVA) was used to compare between groups while controlling demographic variables that significantly differed between groups. A p-value of o 0.05 was considered statistically significant.
3. Results 3.1. Demographical and clinical data The demographic and clinical characteristics of the subjects are presented in Tables 1 and 2. The SSI score was significantly associated with both the BDI (r¼0.65, po0.0001) and the ESI scores (r¼0.43, Table 1 Demographic and clinical characteristics of the participants (n¼ 6977).
2.2. Materials The prevalence of subjective PLE was assessed by the ESI (range 0–102) (Mass, 2000). The ESI is a reliable self-report instrument that measures self-experienced disturbances found in both subjects at risk for psychosis and schizophrenic patients. The ESI comprises 40 items, 34 of which are combined to assess the four domains of PLE symptoms: (1) attention and speech impairment (AS: impairments of the adequate reception and interpretation of environmental stimuli, above all affecting speech); (2) ideas of reference (IR: tendency to interpret trivial events in an excessively meaningful way); (3) auditory uncertainty (AU: inability to discriminate between thoughts and words which have been heard); and (4) deviant perception (DP: alterations of perceptual processes including disturbances of the body image). Moreover, the ESI contains a five-item FR scale that evaluates the tendency to answer questions in a socially desirable manner and one item assessing general survey motivation. The ESI items are answered using a fourpoint Likert scale from 0 (“strongly disagree”) to 3 (“strongly agree”), which are summarized in the subscale scores. The Korean version of ESI has good internal consistencies for the total score and four domains (Cronbach0 s α, 0.70–0.92) and
Raw score
Transformed score
Male % Age (yr) SSI BDI ESI
37.2 16.8 71.1 7.4 7 5.4 10.7 76.9
2.5 71.0a 3.17 1.1a
Total AS AU DP IR
10.3 79.9 4.0 7 3.5 1.9 7 2.4 1.7 7 2.5 2.8 7 5.4
2.9 71.5a 1.8 7 1.0a 1.0 7 0.9a 0.9 70.9a 1.4 7 0.9a
Abbreviations: SSI, scale for suicide ideation; BDI, Beck depression inventory; ESI, Eppendorf schizophrenia inventory; AS, attention and speech impairment; AU, auditory uncertainty; DP, deviant perception; IR, ideas of reference. a
Square-root transformation.
J.H. Jang et al. / Psychiatry Research 215 (2014) 641–645
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Table 2 Correlations among clinical variables in a whole sample.
SSI BDI
BDI
ESI total
AS
AU
DP
IR
0.65nn –
0.43nn 0.55nn
0.35nn 0.49nn
0.35nn 0.042nn
0.36nn 0.042nn
0.39nn 0.48nn
Abbreviations: SSI, scale for suicide ideation; Beck depression inventory; ESI, Eppendorf schizophrenia inventory; AS, attention and speech impairment; AU, auditory uncertainty; DP, deviant perception; IR, ideas of reference. nn
p o0.0001.
Table 3 Summary for the analyses of variables in the path model. 2
B
β
t
Regression of BDI or SSI on ESI Step I: BDI 0.32 Step II: SSI 0.22
0.41 0.32
0.56 0.44
56.39nn 41.78nn
Multiple regression on SSI Step III BDI 0.44 ESI
0.55 0.09
0.56 0.13
51.63nn 11.81nn
R
Abbreviations: BDI, Beck depression inventory; ESI, Eppendorf schizophrenia inventory; SSI, scale for suicide ideation. nn
p o0.0001.
po0.0001). The ESI score was significantly related to the BDI score (r¼ 0.55, po0.0001).
Fig. 1. The direct model represents the results of simple regression analysis. The mediated model represents relationship between PLEs and suicidal ideation as mediated by depressive symptoms. Values on paths are standardized Beta coefficients.nnp o 0.0001. Abbreviation: PLEs, psychotic-like experiences.
Table 4 Comparison of suicidal ideation between high clinical risk subjects for psychotic proneness with low and high depression.
Sex (male %) Age SSIa SSIb
Low depression (n¼ 121)
High depression (n¼ 279)
Statistics d.f.
p
55.4 17.0 (0.8) 2.8 (0.9) 9.01 (5.4)
41.2 16.8 (1.1) 4.0 (0.9) 16.6 (6.9)
χ2 ¼ 6.82 1 0.01 t ¼ 2.16 297.5 0.03 F ¼20.75 1,396 o 0.001
Data are presented as mean (S.D.). Abbreviation: SSI, scale for suicide ideation. a b
Square-root transformation. Raw score.
3.2. Analysis of the mediation model Table 3 summarizes the regression analyses through the three steps to examine an effect of depressive symptoms on the relation between suicidal ideation and PLEs. In the first step, PLEs were significantly associated with depressive symptoms (F3,6973 ¼1104.03, po0.0001). In the second step, the PLEs were found to significantly affect suicidal ideation (F3,6973 ¼655.33, po0.0001). Finally, in the multiple regression equation, the depressive symptoms were found to be significantly related to the suicidal ideation, and the effect of PLEs on suicidal ideation was significant but considerably reduced (F3,6972 ¼1345.86, po0.0001). Additionally, the results of Sobel0 s test indicated that an indirect effect was significant for the SSI (Z¼ 38.00, po0.0001). Fig. 1 illustrates relationship between PLEs and suicidal ideation. When the four subscale scores were put into the model, all four subscores were significantly associated with the depressive symptom (F6,6970 ¼547.15, po0.0001) and the suicidal ideation (F6,6970 ¼327.27, po0.0001). In the multiple regression equation, the depressive symptom was found to be significantly related to the suicidal ideation, and the effect of the AS was not significant and those of the rest scales were reduced (F7,6969 ¼777.52, po0.0001). 3.3. Associations among suicidal ideation, level of PLEs and depression The sample was classified into two groups based on the cutoff score of the ESI: those with a greater intensity of PLEs (total ESI scoreZ29, n ¼400) vs. those with a lesser intensity of PLEs (total ESI scoreo29, n ¼ 6577). There was a significantly higher percentage of boys (45.5% vs. 36.7%; χ2 ¼ 12.62, p ¼0.001) in the greater PLEs group than in the lesser PLEs group, but there was no significant difference in age between the two groups (16.8 vs. 16.8; t¼ 1.26, d.f. ¼454, p ¼0.21). ANCOVA revealed that the subjects with a greater intensity of PLEs had significantly more
Table 5 Comparison of suicidal ideation between depressive subjects with low and high PLEs.
Sex (male %) Age SSIa SSIb
Low PLEs (n¼ 1108)
High PLEs (n¼ 279)
Statistics
d.f.
p
27.3 16.8 (1.0) 3.5 (0.8) 12.8 (5.6)
41.2 16.8 (1.1) 4.0 (0.9) 16.6 (6.9)
χ2 ¼20.3 1 o 0.001 t¼ 0.49 407 0.62 F¼ 101.32 1,1384 o 0.001
Data are presented as mean (S.D.). Abbreviation: PLEs, psychotic-like experiences; SSI, scale for suicide ideation. a b
Square-root transformation. Raw score.
suicidal ideation (SSI raw score: 14.3 vs. 6.9; F1,6974 ¼ 580.70, po 0.0001) and depressive symptoms (BDI raw score: 21.3 vs. 10.0; F1,6974 ¼ 843.71, p o0.0001) than those with a lesser intensity of PLEs. In addition, the subjects with a greater intensity of PLEs were divided into two groups with low (n ¼121) and high (n ¼ 279) depressive symptoms according to the BDI cutoff score (total BDI score Z16). Analysis yielded significantly lower percentage of boys (χ2 ¼ 6.82, d.f. ¼1, p¼ 0.01) and younger subjects (t ¼2.16, d.f. ¼298, po 0.05) in the high depression group than in the low depression group (Table 4). Therefore gender and age variables were controlled in the subsequent analysis. The ANCOVA analysis showed that the subjects with high depressive symptoms had significantly higher SSI scores than those with low depressive symptoms after controlling for gender and age (F (1,396) ¼ 120.75, po 0.001).
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When the SSI scores were compared between the subjects with high level of depressive symptoms who had high (n ¼279) and low ESI total scores (n ¼1108), the subjects with depression who had high ESI score showed significantly higher SSI score than did those with depression who had low ESI score (F (1,1384) ¼101.32, p o0.001), while controlling gender (Table 5).
4. Discussion Our results indicate that PLEs in the early developmental stage are associated with suicidal ideation independent of gender or depressive symptoms. The association between suicidal ideation and PLEs was mediated by depressive symptoms. We also found that intense PLE symptoms are an independent risk factor for suicidal ideation among teenagers. Additionally, DP, IR, and AU were associated with suicidality. To our knowledge, the current study is the largest community-based study to investigate associations between PLEs and the presence of suicidal ideation in adolescents. In this study, PLE was a predictor of high suicidal ideation. Additionally, the level of suicidal ideation was positively associated with the degree of PLEs in adolescents. Teenagers with a greater intensity of PLEs had twice as many SSI scores as did individuals with lesser PLEs. Population-based studies have reported that PLEs are common phenomena in the general population, especially among teenagers (Hanssen et al., 2005; Scott et al., 2006, 2008). The high prevalence of PLEs among adolescents could be explained by exposure to unusual or culturally incongruent ideas that are frequently observed during adolescence (Scott et al., 2006) or abnormal pruning of the brain, mostly in the prefrontal cortex, in late adolescence. Recently, Nishida et al. (2010) reported that 34% of subjects with suicidal ideation experienced PLEs. These results suggest that the experience of PLEs during adolescence may independently predict increased suicidal risk. Furthermore, PLEs in this period are associated with later psychotic disorders and behavioral problems (Poulton et al., 2000; Scott et al., 2008; Kinoshita et al., 2011). The risk of suicide is known to be significantly higher in both individuals at ultra-high-risk for psychosis (Hutton et al., 2011) and patients with psychosis (Palmer et al., 2005; Bertelsen et al., 2007) that warrant early detection and intervention targeting PLEs. This is the first study demonstrating the mediating role of depressive symptoms on the effect of PLEs on suicidal ideation. A recent study investigating associations between PLEs and suicidal risk found that very few of the subjects reported commanding hallucinations to harm or kill themselves (Kelleher et al., 2012b). It could be suggested that PLEs may impact suicidal ideation via indirect mechanisms. Previous studies have reported association between PLEs and symptoms of depression in adolescents (Dhossche et al., 2002; Nishida et al., 2008). Functional and structural neuroimaging studies have emphasized abnormalities in the medial prefrontal cortex and anterior cingulate, that play important roles in emotional regulation, modulation of emotional responses and conflict monitoring, in both individuals with attenuated psychotic symptoms and with depression (Jacobson et al., 2010; Shim et al., 2010; Yoshimura et al., 2010). The adolescents with PLEs may be more sensitive to environmental noises (Nishida et al., 2008). Therefore, the depressive symptoms in adolescents with PLEs could aggravate distortion of sense of reality in social situations, and this distortion may be linked to suicidal ideation. Studies also have suggested increased affective reactivity as well as poorer coping skills to stressful life events in subjects with PLEs as risk factors for suicidal behaviors (Lataster et al., 2009; Lin et al., 2011). However, future work will
be warranted to investigate biological underpinnings of suicidal behaviors. The present research sample of mid- to late teenagers (14–19 years of age) was, as far as we know, the largest ever examined in this type of study. In many cases, the first psychotic episode occurs around the age of 20 years. Therefore, early detection should start in mid- to late adolescence, ages that were included in the present study. This could be regarded as a strength of this study from a clinical perspective compared with the previous studies, which included subjects in their early teens. Subclinical psychotic symptoms and signs are more likely to be overlooked than depression (Houston et al., 2001; Nishida et al., 2010). Clinicians should focus on the presence of both PLEs and depressive symptoms in adolescents. The current study is also the first to reveal that perceptual/ cognitive domains (i.e., DP and AU) as well as thought-content disturbances (i.e., IR) of ESI are related to high suicidality. The present results indicate that each PLE domain could independently predict suicidal ideation. The DP and AU subscales refer to aberrations in perceptual processes, especially those involving disturbances of self-image and discrimination between thoughts and words that have actually been heard, respectively. The IR subscale represents a tendency to interpret ordinary events in excessively meaningful or delusional ways. These subscales are regarded as indicators of psychotic exacerbations (Mass et al., 2005). Our results suggest that the presence of perceptual disturbances and referential ideas in adolescents could be regarded as a warning sign for suicide-related behaviors. There are several limitations of this study. First, we used selfreport questionnaires and could not found the prevalence of frank psychosis. Screening via self-reports has a potential to overestimate the actual risk for subsequent psychosis compared with the interview-based surveys (Kendler et al., 1996). Moreover, the possibility that some portion of participants were having psychosis, such as schizophrenia or major depressive disorder with psychotic symptoms, could not be excluded. However, face-toface interviews are impractical for large-scale population-based studies like this one. Second, as a result of the cross-sectional nature of this study, information about longitudinal causal direction was not available. A longitudinal study might be warranted to evaluate subsequent suicidal behaviors and transition to psychosis in young individuals with PLEs. Another area of concern involves the sample representativeness, as female or high school students were majority of our participants. To investigate the true prevalence of PLEs in Korea, future study with more representative sample should be needed. Last, because of the large sample size of this study, relatively small associations between clinical variables could be shown statistically significant. In conclusion, we found that PLE among adolescents was a predictor of suicidal ideation, mediated by depressive symptoms. Our study emphasizes the necessity of early detection and intervention for adolescents with PLEs. Therefore, future longitudinal studies are warranted to focus on early intervention and prevention of subclinical psychotic symptoms and depressive symptoms in adolescents.
References Baron, R.M., Kenny, D.A., 1986. The moderator-mediator variable distinction in social psychological research: conceptual, strategic, and statistical considerations. Journal of Personality and Social Psychology 51, 1173–1182. Beck, A.T., Brown, G.K., Steer, R.A., 1997. Psychometric characteristics of the Scale for Suicide Ideation with psychiatric outpatients. Behaviour Research and Therapy 35, 1039–1046. Beck, A.T., Kovacs, M., Weissman, A., 1979. Assessment of suicidal intention: the Scale for Suicide Ideation. Journal of Consulting and Clinical Psychology 47, 343–352.
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Beck, A.T., Ward, C.H., Mendelson, M., Mock, J., Erbaugh, J., 1961. An inventory for measuring depression. Archives of General Psychiatry 4, 561–571. Bertelsen, M., Jeppesen, P., Petersen, L., Thorup, A., Ohlenschlaeger, J., le Quach, P., Christensen, T.O., Krarup, G., Jorgensen, P., Nordentoft, M., 2007. Suicidal behaviour and mortality in first-episode psychosis: the OPUS trial. The British Journal of Psychiatry Supplement 51, s140–146. Bijl, R.V., van Zessen, G., Ravelli, A., de Rijk, C., Langendoen, Y., 1998. The Netherlands Mental Health Survey and Incidence Study (NEMESIS): objectives and design. Social Psychiatry and Psychiatric Epidemiology 33, 581–586. Chung, Y.C., Kang, N.I., Im, Y.J., Kim, S.W., Cho, I.H., Lee, Y.M., Kwon, J.S., 2013. Validation of the Korean version of the Eppendorf Schizophrenia Inventory as a screening measure to detect adolescents at ultra-high risk for psychosis. Early Intervention in Psychiatry 7, 71–79. Dhossche, D., Ferdinand, R., Van der Ende, J., Hofstra, M.B., Verhulst, F., 2002. Diagnostic outcome of self-reported hallucinations in a community sample of adolescents. Psychological Medicine 32, 619–627. Hahn, H.M., Yum, T.H., Shin, Y.W., Kim, K.H., Yoon, D.J., Chung, K.J., 2002. A standardization study of Beck Depression Inventory in Korea. Journal of Korean Neuropsychiatric Association 41, 487–502. Hanssen, M., Bak, M., Bijl, R., Vollebergh, W., van Os, J., 2005. The incidence and outcome of subclinical psychotic experiences in the general population. The British Journal of Clinical Psychology 44, 181–191. Hanssen, M.S., Bijl, R.V., Vollebergh, W., van Os, J., 2003. Self-reported psychotic experiences in the general population: a valid screening tool for DSM-III-R psychotic disorders? Acta Psychiatrica Scandinavica 107, 369–377. Haroun, N., Dunn, L., Haroun, A., Cadenhead, K.S., 2006. Risk and protection in prodromal schizophrenia: ethical implications for clinical practice and future research. Schizophrenia Bulletin 32, 166–178. Harvey, S.B., Dean, K., Morgan, C., Walsh, E., Demjaha, A., Dazzan, P., Morgan, K., Lloyd, T., Fearon, P., Jones, P.B., Murray, R.M., 2008. Self-harm in first-episode psychosis. The British Journal of Psychiatry 192, 178–184. Houston, K., Hawton, K., Shepperd, R., 2001. Suicide in young people aged 15-24: a psychological autopsy study. Journal of Affective Disorders 63, 159–170. Hutton, P., Bowe, S., Parker, S., Ford, S., 2011. Prevalence of suicide risk factors in people at ultra-high risk of developing psychosis: a service audit. Early Intervention in Psychiatry 5, 375–380. Jacobson, S., Kelleher, I., Harley, M., Murtagh, A., Clarke, M., Blanchard, M., Connolly, C., O’Hanlon, E., Garavan, H., Cannon, M., 2010. Structural and functional brain correlates of subclinical psychotic symptoms in 11–13 year old schoolchildren. NeuroImage 49, 1875–1885. Johns, L.C., Cannon, M., Singleton, N., Murray, R.M., Farrell, M., Brugha, T., Bebbington, P., Jenkins, R., Meltzer, H., 2004. Prevalence and correlates of self-reported psychotic symptoms in the British population. The British Journal of Psychiatry 185, 298–305. Kelleher, I., Connor, D., Clarke, M.C., Devlin, N., Harley, M., Cannon, M., 2012a. Prevalence of psychotic symptoms in childhood and adolescence: a systematic review and meta-analysis of population-based studies. Psychological Medicine 42, 1857–1864. Kelleher, I., Lynch, F., Harley, M., Molloy, C., Roddy, S., Fitzpatrick, C., Cannon, M., 2012b. Psychotic symptoms in adolescence index risk for suicidal behavior: findings from 2 population-based case-control clinical interview studies. Archives of General Psychiatry 69, 1277–1283. Kelleher, I., Corcoran, P., Keeley, H., Wigman, J.T., Devlin, N., Ramsay, H., Wasserman, C., Carli, V., Sarchiapone, M., Hoven, C., Wasserman, D., Cannon, M., 2013. Psychotic symptoms and population risk for suicide attempt: a prospective cohort study. JAMA Psychiatry 70, 940–948. Kendler, K.S., Gallagher, T.J., Abelson, J.M., Kessler, R.C., 1996. Lifetime prevalence, demographic risk factors, and diagnostic validity of nonaffective psychosis as assessed in a US community sample. the National Comorbidity Survey. Archives of General Psychiatry 53, 1022–1031. Kinoshita, Y., Shimodera, S., Nishida, A., Kinoshita, K., Watanabe, N., Oshima, N., Akechi, T., Sasaki, T., Inoue, S., Furukawa, T.A., Okazaki, Y., 2011. Psychotic-like experiences are associated with violent behavior in adolescents. Schizophrenia Research 126, 245–251. Klosterkötter, J., Hellmich, M., Steinmeyer, E.M., Schultze-Lutter, F., 2001. Diagnosing schizophrenia in the initial prodromal phase. Archives of General Psychiatry 58, 158–164. Kwon, J.W., Chun, H., Cho, S.I., 2009. A closer look at the increase in suicide rates in South Korea from 1986–2005. BMC Public Health 9, 72. Lataster, T., Wichers, M., Jacobs, N., Mengelers, R., Derom, C., Thiery, E., Van Os, J., Myin-Germeys, I., 2009. Does reactivity to stress cosegregate with subclinical
645
psychosis? A general population twin study. Acta Psychiatrica Scandinavica 119, 45–53. Lee, H.S., Kwon, J.H., 2009. Validation for the Beck Scale for Suicide Ideation with Korean university students. Korean Journal of Clinical Psychology 28, 1155–1172. Lin, A., Wigman, J.T., Nelson, B., Vollebergh, W.A., van Os, J., Baksheev, G., Ryan, J., Raaijmakers, Q.A., Thompson, A., Yung, A.R., 2011. The relationship between coping and subclinical psychotic experiences in adolescents from the general population: a longitudinal study. Psychological Medicine 41, 2535–2546. Mass, R., 2000. Characteristic subjective experiences of schizophrenia. Schizophrenia Bulletin 26, 921. Mass, R., Haasen, C., Borgart, E.J., 2005. Abnormal subjective experiences of schizophrenia: evaluation of the Eppendorf Schizophrenia Inventory. Psychiatry Research 135, 91–101. Mass, R., Haasen, C., Wolf, K., 2000. [The Eppendorf Schizophrenia Inventory (ESI). Development and evaluation of a questionnaire for assessment of characteristic self perception of cognitive dysfunctions by schizophrenic patients]. Der Nervenarzt 71, 885–892. Nishida, A., Sasaki, T., Nishimura, Y., Tanii, H., Hara, N., Inoue, K., Yamada, T., Takami, T., Shimodera, S., Itokawa, M., Asukai, N., Okazaki, Y., 2010. Psychotic-like experiences are associated with suicidal feelings and deliberate self-harm behaviors in adolescents aged 12–15 years. Acta Psychiatrica Scandinavica 121, 301–307. Nishida, A., Tanii, H., Nishimura, Y., Kajiki, N., Inoue, K., Okada, M., Sasaki, T., Okazaki, Y., 2008. Associations between psychotic-like experiences and mental health status and other psychopathologies among Japanese early teens. Schizophrenia Research 99, 125–133. Palmer, B.A., Pankratz, V.S., Bostwick, J.M., 2005. The lifetime risk of suicide in schizophrenia: a reexamination. Archives of General Psychiatry 62, 247–253. Poulton, R., Caspi, A., Moffitt, T.E., Cannon, M., Murray, R., Harrington, H., 2000. Children0 s self-reported psychotic symptoms and adult schizophreniform disorder: a 15-year longitudinal study. Archives of General Psychiatry 57, 1053–1058. Preacher, K.J., Hayes, A.F., 2004. SPSS and SAS procedures for estimating indirect effects in simple mediation models. Behavior Research Methods, Instruments, & Computers 36, 717–731. Scott, J., Chant, D., Andrews, G., McGrath, J., 2006. Psychotic-like experiences in the general community: the correlates of CIDI psychosis screen items in an Australian sample. Psychological Medicine 36, 231–238. Scott, J., Welham, J., Martin, G., Bor, W., Najman, J., O’Callaghan, M., Williams, G., Aird, R., McGrath, J., 2008. Demographic correlates of psychotic-like experiences in young Australian adults. Acta Psychiatrica Scandinavica 118, 230–237. Shim, G., Oh, J.S., Jung, W.H., Jang, J.H., Choi, C.H., Kim, E., Park, H.Y., Choi, J.S., Jung, M.H., Kwon, J.S., 2010. Altered resting-state connectivity in subjects at ultrahigh risk for psychosis: an fMRI study. Behavioral and Brain Functions 6, 58. Shin, M.S., Kim, J.S., Park, K.B., 1993. The cutoff score of the Korean version of Beck Depression Inventory. Korean Journal of Clinical Psychology 12, 71–81. Song, Y.Y., Kim, K.R., Park, J.Y., Lee, S.Y., Kang, J.I., Lee, E., An, S.K., Kwon, J.S., 2011. Associated factors of quality of life in first-episode schizophrenia patients. Psychiatry Investigation 8, 201–206. Thompson, M.P., Light, L.S., 2011. Examining gender differences in risk factors for suicide attempts made 1 and 7 years later in a nationally representative sample. The Journal of Adolescent Health 48, 391–397. van Os, J., Linscott, R.J., Myin-Germeys, I., Delespaul, P., Krabbendam, L., 2009. A systematic review and meta-analysis of the psychosis continuum: evidence for a psychosis proneness-persistence-impairment model of psychotic disorder. Psychological Medicine 39, 179–195. Xing, X.Y., Tao, F.B., Wan, Y.H., Xing, C., Qi, X.Y., Hao, J.H., Su, P.Y., Pan, H.F., Huang, L., 2010. Family factors associated with suicide attempts among Chinese adolescent students: a national cross-sectional survey. The Journal of Adolescent Health 46, 592–599. Yoshimura, S., Okamoto, Y., Onoda, K., Matsunaga, M., Ueda, K., Suzuki, S., Yamawaki, S., 2010. Rostral anterior cingulate cortex activity mediates the relationship between the depressive symptoms and the medial prefrontal cortex activity. Journal of Affective Disorders 122, 76–85. Yung, A.R., Buckby, J.A., Cotton, S.M., Cosgrave, E.M., Killackey, E.J., Stanford, C., Godfrey, K., McGorry, P.D., 2006. Psychotic-like experiences in nonpsychotic help-seekers: associations with distress, depression, and disability. Schizophrenia Bulletin 32, 352–359. Yung, A.R., Nelson, B., Baker, K., Buckby, J.A., Baksheev, G., Cosgrave, E.M., 2009. Psychotic-like experiences in a community sample of adolescents: implications for the continuum model of psychosis and prediction of schizophrenia. Australian and New Zealand Journal of Psychiatry 43, 118–128.
