Obesity Research & Clinical Practice (2012) 6, e139—e147
ORIGINAL ARTICLE
Depression, anxiety, and neuroticism in obese patients waiting for bariatric surgery: Differences between patients with and without eating disorders and subthreshold binge eating disorders Jens K. Dahl a,b,∗, Lasse Eriksen a,c, Einar Vedul-Kjelsås a,b, Magnus Strømmen a,d, Bård Kulseng d, Ronald Mårvik d, Are Holen a,e a
Department of Neuroscience, Faculty of Medicine, Norwegian University of Science and Technology NTNU, N-7006 Trondheim, Norway b Department of Research and Development, AFFU, St. Olavs University Hospital, Division of Psychiatry, Østmarka, N-7006 Trondheim, Norway c Department of Nidaros DPS, St. Olavs University Hospital, Division of Psychiatry, N-7440 Trondheim, Norway d Centre for Obesity, St. Olavs University Hospital, N-7006 Trondheim, Norway e Pain Care Unit, St. Olavs University Hospital, N-7006 Trondheim, Norway Received 23 March 2011 ; received in revised form 14 July 2011; accepted 18 July 2011
KEYWORDS Obesity; Eating disorders; Bariatric surgery; Neuroticism; Anxiety and depression
Summary Objective: This study investigated self-reported levels of depression, anxiety and neuroticism in obese patients waiting for bariatric surgery. The patients who indicated that they might have eating disorders (ED) or subthreshold binge eating disorders (SBED) were compared with those without. Method: The design was cross sectional. Obese patients (n = 160, 117 women, 43 men) returned self-report questionnaires: Eating Disorders in Obesity (EDO) indicated eating disorder status; Hospital Anxiety and Depression Scale (HADS) assessed symptoms and caseness of depression and anxiety; and the Eysenck Personality Questionnaire (EPQ-12) captured neuroticism. Age, BMI and gender were also recorded. Results: Patients with ED (n = 28) presented significantly higher levels of depression, anxiety and neuroticism as well as more HADS-cases for depression and anxiety than those without ED (n = 109). Patients with sub-diagnostic binge eating disorders (SBED, n = 23) also reported significantly more depression symptom levels, and number of HADS-cases of depression, than those without ED. In addition, the SBED group showed
∗ Corresponding author at: Department of Research and Development, St. Olavs University Hospital, Division of Psychiatry, P.O. Box 3008 Lade, N-7441 Trondheim, Norway. Tel.: +47 72 82 30 30; fax: +47 72 82 30 46. E-mail address: [email protected] (J.K. Dahl).
1871-403X/$ — see front matter © 2011 Asian Oceanian Association for the Study of Obesity. Published by Elsevier Ltd. All rights reserved.
doi:10.1016/j.orcp.2011.07.005
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J.K. Dahl et al. significantly more neuroticism than patients without ED. No significant differences were found between men and women, for high/low age, or for high/low BMI. Conclusion: The data displayed that obese pre-surgery patients with eating disorders have more psychological problems than those without. Patients with SBED were more similar to those with full scale eating disorders in their level of depression and neuroticism than those without ED. Clinically, obese patients with SBED should probably be regarded as those who have full scale ED. © 2011 Asian Oceanian Association for the Study of Obesity. Published by Elsevier Ltd. All rights reserved.
Introduction Approximately 50% of obese patients who sought bariatric surgery reported comorbid psychopathology that was in accordance with the DSM-IV criteria, Axis I [1,2]. Mood and anxiety disorders have been reported in about 20% [3,4] and Binge Eating Disorder (BED) has commonly been found in 16—30% of the obese patients who seek surgical weight loss treatment [5,6]. There are several reasons that eating disorders are of particular interest in the obese pre-surgery patients. Firstly, binge eating seems to induce obesity. Secondly, BED is assumed to negatively influence the outcome of the surgical procedures. Uncontrolled eating is not in accordance with the behavioral recommendations after bariatric surgery [6]. Thirdly, obese patients with eating disorders tend to have more psychiatric distress than those without eating disorders [4,7], which indicates a need for psychological treatment. Among the obese patients seeking surgery, three eating disorders are common: Bulimia Nervosa (BN), Eating Disorder Not Otherwise Specified (EDNOS), and the sub-category of EDNOS called Binge Eating Disorder (BED) presented in the appendix of DSM-IV-TR [8]. In the pre-surgery population, BED is the most studied [6]. The proposed diagnostic criteria for BED include episodes of binge eating, i.e., the intake of large amounts of food within 2 h, together with a sense of lost control over eating. BED is not associated with inappropriate compensatory behaviors, as is BN. The clinical relevance of low frequency binge eating or subthreshold eating disorders among patients seeking bariatric surgery has been debated. From a non-surgical obese sample, sub-diagnostic binge eating was associated with more psychiatric comorbidity [9]. According to one review article, sub-diagnostic binge eating is more prevalent than BED in patients seeking surgical treatment, the reported prevalence has varied from 6% to 64% [6]. Obese pre-surgery patients with eating disorders show Axis I comorbidity more often than those without eating disorders [10—12]. The diag-
nostic criteria for other psychiatric disorders are met among 66.7% of patients with eating disorders compared to 26.7% among those without eating disorders [4]. More concern about shape, weight and unfavorable treatment outcomes have been reported from binge eaters than from non-binge eaters [10—13]. Higher levels of self-reported psychiatric symptoms and lower quality of life in obese patients with binge eating disorders compared to patients without have been reported [14,15]. Accordingly, researchers have suggested that obese patients with eating disorders should be considered a separate diagnostic entity with specific needs in the weight-loss treatment [9,12,16]. Further investigation into the psychological functioning of obese patients with and without eating disorders seems warranted.
Personality traits Personality traits can be defined as: ‘‘enduring dimensions of individual differences in tendencies to show consistent patterns of thoughts, feelings, and actions’’ [17]. Efforts to find the ‘‘personality’’ of the morbidly obese have failed. However, some reports indicate that the morbidly obese have more personality problems than those in the general population [18,19]. One report concluded that the obese do not differ from the general population on non-weight-related personality traits [20]. In several other studies, associations between personality traits and eating disorders have been found [21,22]. The personality trait ‘‘neuroticism’’ is defined as the propensity to experience negative emotions [23]. It has consistently been recognized as one of the main dimensions of personality [24] and is captured by personality inventories such as Eysenck Personality Questionnaire (EPQ) and NEO Personality Inventory Revised (NEO PI-R) [25]. In the EPQ and NEO-PI-R questionnaires, neuroticism is represented by emotional instability, anxiousness, guilt feelings, low self-esteem, hypersensitivity, tension,
Depression, anxiety, and neuroticism in obese patients shyness, and emotionalism [23,26]. Positive associations between neuroticism and eating disorders have also been demonstrated [22,27,28], while the results regarding associations between neuroticism and obesity have been mixed [21,29,30]. High levels of neuroticism seem to increase body dissatisfaction and destructive eating behaviors [31]. Exposure to adverse life events can increase negative affects. In obese patients this may result in negative feelings about their appearance and instigate overeating. A literature search on obese pre-surgery patients revealed no prior investigations of patients with and without eating disorders that also included measures of neuroticism. Most studies on the associations between personality and eating disorders have focused on anorexia nervosa and bulimia nervosa [22]. Less research has been done on personality variables in patients who are prone to binge eating [22]. Previous studies concerning obese pre-surgery patients have exclusively studied the associations between BED or binge eating behavior and psychological distress [5,6,32]. Few studies have tried to distinguish between the eating disorders. In the present study, all the relevant DSM-IVTR eating disorder diagnoses were included. Two groups of obese patients, those indicating eating disorders and those indicating subthreshold binge eating disorders (SBED), were compared with patients without any eating disorders. They were contrasted with regard to depression, anxiety, neuroticism, and the occurrence of HADS-cases of depression and anxiety. In the explorative part of the study, depression, anxiety, and neuroticism were investigated in relation to age, BMI, and gender. The directional hypotheses were as follows: (1) Patients indicating eating disorders will report more depression, anxiety and neuroticism than those without eating disorders. (2) Patients indicating subthreshold binge eating disorders will report more depression, anxiety, and neuroticism than those without eating disorders.
Methods Participants, procedures, and design Questionnaires were mailed to 209 morbidly obese patients waiting for bariatric surgery at St. Olavs University Hospital, Norway. One reminder was sent by mail. In 2005, the participants gave their informed consent. The response rate was 76.5%;
e141 160 completed their questionnaires. Of the participants, 117 (73.1%) were women and 43 (26.9%) were men. Mean age and BMI for the total sample were, respectively, 41.1 (SD = 10.4) and 47.2 (SD = 5.8). For further descriptions of the patient characteristics, see Dahl et al. [33]. Their responses had no bearing upon the preoperative approval process. The inclusion criteria for gastric bypass surgery were: BMI (kg/m2 ) between 35 and 40 plus one obesity-related somatic comorbidity or BMI ≥ 40. Patients who fulfilled any of the following criteria were excluded: severe mental disorders except eating disorders, pregnancy, prior bariatric surgery, substance abuse, or dependence on a wheelchair or crutches. The study was cross-sectional and based on self-reports. Approval from the Regional Committee for Research Ethics in Central Norway was given for the study.
Assessments of eating disorders Eating Disorders in Obesity (EDO) is an 11-item self-report questionnaire designed to detect any type of eating disorder in obese populations [34]. The questionnaire was developed from the ‘‘Survey of the Eating Disorders’’ (SEDs) by Gotestam and Agras and is based on the DSM-IV criteria [35]. The EDO is an adjusted short version of the SEDs that excludes questions about anorectic symptoms as underweight is irrelevant for obese patients. For the sake of clarity, the questionnaire starts with a definition of binge eating. EDO has good test-retest reliability and validity in relation to EDE [36]. With a 14-day interval in a student sample, the testretest reliability showed complete convergence of the derived diagnoses between the first and second response to EDO [34]. In this study, the EDO was used to identify three eating disorder diagnoses: Bulimia Nervosa (BN, n = 1), Binge Eating Disorder (BED, n = 21), and Eating Disorder Not Otherwise Specified (EDNOS, n = 6). Those who fulfilled the criteria were regarded as indicating eating disorders (ED). Patients who were one criterion short of the BN diagnosis were considered as having EDNOS. Five of six patients in this category matched the description of EDNOS example 3 in the DSM-IV-TR: ‘‘All the criteria for Bulimia Nervosa are met except that the binge eating and inappropriate compensatory mechanisms occur at a frequency of less than twice a week or for a duration of less than 3 months’’ [8]. One patient, who lacked a criterion of the BN diagnosis other than what has been specified in example 3 in DSM-IV-TR (self-evaluation is unduly influenced by body shape and weight), was categorized as having EDNOS. This person was included since EDNOS originally was
e142 intended to serve as a residual category for eating disorders previously neglected by most researchers [37]. In addition, a subthreshold diagnostic group called Subthreshold binge eating disorder (SBED, n = 23) was included. The category was made by the authors and consisted of those who were one criterion short of the BED diagnosis. This entity is not part of the DSM manual, though at times it is reported as a specific category [16] or included in the BED diagnosis when more liberal criteria are applied [15]. The 160 patients were divided into three groups: Group 1 was ‘‘ED’’ (n = 28) and fulfilled the criteria of BN, EDNOS, or BED: Group 2 was called ‘‘SBED’’ (n = 23) and lacked one of the criteria for BED, namely Subthreshold binge eating disorder; and Group 3 was called ‘‘Not ED-SBED’’ (n = 109) as they were without any eating disorder (ED) and also without any subthreshold binge eating disorder. Group 1 and 2 were tested for Mean Differences in scores on the dependent variables against Group 3. In the present paper, the patients in Group 3 ‘‘Not ED-SBED’’ (n = 109) is referred to as ‘‘without eating disorders’’. Accordingly, the 23 patients with SBED are not included in the group called ‘‘without eating disorders’’.
Instruments Hospital Anxiety and Depression Scale (HADS) is a widely used self-report instrument for psychiatric distress [38]. The scale has 14 items that cover the last week. The two subscales, with seven items each, measure the person’s degree of depression (HADS-Depression) and anxiety (HADSAnxiety). Each item is scored from 0 to 3; higher scores represent higher levels of distress [38]. The clinically tested classification system developed for HADS considers a score of 0—7 on a sub-scale to be within the normal range, a score of 8—10 to be ‘‘a possible case’’, and a score of 11 or more to be a case of depression or anxiety [38]. In the present study, the criterion for a HADS-case of depression or anxiety was a score ≥11 for each scale, while Olssøn et al. applied a score of ≥8 [39]. Caseness indicates that a psychiatric diagnosis is quite likely. In the present study, the Cronbach’s alpha of HADSDepression was .75 and HADS-Anxiety was .84. Eysenck Personality Questionnaire (EPQ-12) is a twelve item self-report instrument derived from the EPQ 90-item version [40]. The EPQ-12 assesses the personality trait neuroticism [41]. Each item is rated as 1-‘yes’ or 0-‘no’. The potential score range is 0—12. In the present study, the Cronbach’s alpha of the EPQ-12 was .84.
J.K. Dahl et al. Information about age, BMI, and gender was also obtained. Studies have shown that overweight participants tend to underestimate their weight [42]. However, self-reported BMI seems to be fairly accurate when assessing the prevalence of overweight and obesity [43].
Statistics It is recommend that focused statistical tests are applied and that omnibus tests should be avoided [44—46]. In the present study, these recommendations were followed. Inferential statistics were applied by independent-samples t-tests (twotailed). Statistical tests were two-tailed in spite of the directional hypotheses since there is a close link between the use of the confidence interval and the two-sided hypothesis test (significance test) [47]. For the categorical variables, twotailed chi-squared tests with two samples (unpaired case, df = 1) were applied. Low numbers in some subgroups limited the statistical power; this is reflected in the wider confidence intervals. In the explorative part of the study, Pearson’s bivariate correlations (two-tailed) for continuous variables were applied. In addition, the dichotomous variables covering high/low age and high/low BMI were defined by the median split. Independent ttests were employed for the differences in anxiety, depression and neuroticism between patients with high/low age or high/low BMI and also between women and men. The alpha level was set to p ≤ .05 with exact p-values reported [46]. The t-test is not valid when the sample size of the two groups are too uneven and when the groups have significantly different variances [44,45]. The Mann—Whitney U Test was therefore applied for one comparison of the anxiety scores. For the t-test and chi-square tests, d and phi were calculated for the effect sizes. Cohen’s norms were applied for the effect sizes [44]. The confidence intervals for the proportions and their differences were computed with the recommended method in Newcombe and Altmann [48]. SPSS 16 for Windows was applied in the statistical analyses. There were missing responses in the EDO for two women and one man. It was impossible to diagnose their ED. The three participants were included in the data analyses as not having eating disorders. If one or more of the undiagnosed patients had an eating disorder or subthreshold binge eating disorder (SBED), this procedure would make it less likely to find significant differences between the groups. There were no missing responses in age, but four missing responses for BMI: the values were replaced by the groups mean BMI. There were 7
f
e
c
d
ED = Eating Disorder: Bulimia Nervosa (BN) + Binge Eating Disorder (BED) + Eating Disorder Not Otherwise Specified (EDNOS). SBED = Subthreshold Binge Eating Disorder (Respondents lacking one diagnostic criterion for BED). Not ED-SBED = Respondents with neither Eating Disorder nor Subthreshold Binge Eating Disorder. Depression and anxiety: Hospital Anxiety and Depression Scale (HADS). Neuroticism: Eysenck Personality Questionnaire (EPQ-12). Mann—Whitney U Test (two-tailed). a
HADS-Depression HADS-Anxiety Neuroticism
Neuroticisme
b
95% CI
[.087, 3.44] [−.22,3.56] [.33, 3.28] .48 .37 .55
d p
.039 .082 .017 130 130 128
df t
2.08 1.75 2.43 6.36 (3.70) 7.28 (4.00) 5.14 (3.22) 8.13 (3.62) 8.95 (4.84) 6.95 (3.30)
[1.11,3.80] .78 .001 133
Not ED-SBED n = 109 Mean (SD) SBEDb n = 23 Mean (SD)
3.62
[.77, 4.00] — .59 .18 .004 .032 135 —
95% CI d/r p df t/z
2.93 2.14f
6.36 (3.70) 7.28 (4.00) Median 7.00 5.14 (3.22) 8.75 (4.32) 9.46 (5.38) Median 10.50 7.60 (3.09) HADS-Depression HADS- Anxietyd
d
The patients with an indication of having ED reported significantly higher scores on the HADSDepression scale than the patients without ED, t (135) = 2.93, p = .004, d = .59, Mean Difference 2.38, 95% CI [.774, 4.00]. Patients indicating ED also reported significantly higher scores on the HADS-Anxiety scale than those without ED (Mann—Whitney U Test), z = 2.14, p = .032, r = .18. Moreover, the patients indicating ED had significantly higher scores on neuroticism than the patients without ED, t (133) = 3.62, p = .001, d = .78, Mean Difference 2.45, 95% CI [1.11, 3.80]. (See Table 1). Patients indicating SBED had significantly higher scores on HADS-Depression than patients without ED, t (130) = 2.08, p = .039, d = .48, Mean Difference 1.76, 95% CI [.087, 3.44]. No significant differences in HADS-Anxiety were found between patients in the SBED group and those without ED. The patients with SBED had significantly higher scores on neuroticism than the patients without ED, t (128) = 2.43, p = .017, d = .55, Mean Difference 1.81, 95% CI [.33, 3.28]. Subsequent analyses showed no significant differences between the patients diagnosed with ED and those categorized as SBED patients, with regards to scores on HADS-Depression, HADSAnxiety, and neuroticism. The number of HADS-cases with depression was significantly higher in the ED group and the SBED group than in the group of patients without eating disorders. Significantly more HADS-cases with anxiety were found among patients in the ED group, but not in the SBED group compared to patients without ED. Table 2 showed how the HADS-cases of depression and anxiety were distributed in the three categories of eating behaviors. In the subsequent analyses of the HADS-cases for depression and anxiety, no significant differences
Not ED-SBEDc n = 109 Mean (SD)
Results
e143
EDa n = 28 Mean (SD)
missing responses in the HADS-Depression, 5 in the HADS-Anxiety, and 18 in EPQ-12. In each of the three scales, the missing responses were replaced by mean scores. Patients with more than two missing responses were excluded from the data analyses [38]. For the HADS subscales, no patient had more than two missing responses. In the EPQ-12, three patients were excluded from the analyses due to missing endorsements. The remaining patients with missing responses on EPQ-12 were included in the analyses: one had two missing responses and 6 had one missing response.
Table 1 Comparisons between three groups of obese pre-surgery patients categorized according to their self-reported eating behaviors, their HADS-scores on depression and anxiety and their EPQ-12 score on neuroticism. The differences were computed by independent two-tailed t-tests or two-tailed Mann—Whitney U Test.
Depression, anxiety, and neuroticism in obese patients
[.029, .43] [−.019,.38]
95% CI
c
d
a
b
ED = Eating Disorder: Bulimia Nervosa (BN) + Binge Eating Disorder (BED) + Eating Disorder Not Otherwise Specified (EDNOS). SBED = Subthreshold Binge Eating Disorder (Respondents lacking one diagnostic criterion for BED). Not ED-SBED = Respondents with neither Eating Disorder nor Subthreshold Binge Eating Disorder. HADS-case = Patients with a score of 11 or more on HADS-Depression or HADS-Anxiety, indicates a case in need of further assessment and treatment.
.20 .15 .021 .085 5.35 2.97 %
17.43 20.18 19 24 39.13 39.13
HADS-casesd
Not ED-SBED n = 109
% HADS-casesd
9 9 HADS-Depression HADS-Anxiety
p 2
phi
.035 .003 4.46 8.70
SBEDb n = 23
%
17.43 20.18 19 24 35.71 50.00
HADS-casesd
Not ED-SBEDc n = 109
% HADS-casesd
10 14 HADS-Depression HADS-Anxiety
2
p
.18 .25
phi
95% CI
[.012, .38] [.086, .47]
J.K. Dahl et al.
EDa n = 28
Table 2 Obese patients waiting for bariatric surgery categorized into three groups according to self-reported eating behaviors. Differences in HADS-cases of depression and of anxiety within each group are displayed. (Chi-square tests, two samples, df = 1).
e144
were found between patients categorized with ED compared with those of the SBED group. In the explorative part of the study, no significant differences between men and women were found for the scores on HADS-Depression, or HADSAnxiety, or neuroticism. The same was true for patients with high versus low age, and high versus low BMI. Similarly, correlating HADS-Depression, HADS-Anxiety, and neuroticism with age and BMI gave correlations (two-tailed) from −.25 to .23. Likewise, no significant differences were found in the number of HADS-cases among men and women, or in the total sample between high and low age, or between high and low BMI. Among the 117 women, 28 HADS-cases of depression (23.93%) and 38 HADS-cases of anxiety (32.47%) were identified. There were 9 HADS-cases of depression (20.93%), and 9 HADS-cases of anxiety (20.93%) among the 43 men. In total, 37 of 160 patients (23.1%) qualified as HADS-cases of depression, and 47 patients of the 160 patients (29.4%) qualified as HADS-cases of anxiety. There were moderate positive correlations between HADS-Anxiety and HADS-Depression (r = .60, 36% shared variance), and between HADSDepression and neuroticism (r = .62, 38% shared variance). A high positive correlation between HADS-Anxiety and neuroticism (r = .78, 61% shared variance) was also found [49].
Discussion The findings support the hypothesis that those with eating disorders have more depression, anxiety and neuroticism than those without. The obese patients with ED also emerged with more HADS-cases for depression and for anxiety than those without. In addition, the findings suggest that patients with SBED report more depression and neuroticism and more HADS-cases of depression than patients without ED, which is in accordance with the hypothesis. According to Cohen’s norms [44], the effect sizes for the differences in depression and neuroticism between patients with and without eating disorders and between patients with SBED and without ED were almost moderate to almost large. This underscores the clinical relevance of the differences between patients with and without ED and SBED. In the explorative part of the study, no differences in anxiety, depression, or neuroticism were found between men and women, between patients with high/low age, or between high/low BMI. These variables are apparently unlikely to explain why
Depression, anxiety, and neuroticism in obese patients patients with eating disorders report more depression, anxiety, and neuroticism than those without. In the subsequent analysis between the patients with ED versus SBED, no differences were found in their levels of depression, anxiety, and neuroticism. The absence of significant differences between the groups may be due to low statistical power in the ttests. However, the p-values for depression, anxiety and neuroticism were .59, .73 and. 47. Accordingly, it seems unlikely that more participants in each group would have given different results in these comparisons. Hence, the data do not indicate that those with ED and SBED are essentially different on these parameters. Both when categorized as HADS-cases of depression or anxiety and when HADS was used as continuous variables, differences were found between those with and without eating disorders. The observation is strengthened by the differences found for neuroticism. Together these findings emphasize that there is a distinction between patients with eating disorders and patients without eating disorders. Patients with ED experience more psychological problems than those without eating disorders. The findings are in accordance with prior studies that showed more Axis I disorders and more psychiatric symptoms among the obese patients with eating disorders [9,14,27]. Patients with eating disorders appear to be more psychologically vulnerable, and thus, they seem to constitute a distinctive group within the obese population.
Neuroticism Patients indicating eating disorders (BN, BED, EDNOS), as well as those who indicated subthreshold binge eating disorders (SBED), displayed higher levels of neuroticism than those without ED. This is in accordance with a study by Bulik et al. [27]. The present findings suggest that more neurotic personalities are found among the obese patients with eating disorders. Resent research suggests that a neurotic predisposition, measured by NEOPI-R, restrains weight reduction and psychological adjustments after bariatric surgery [50]. Their emotional over-reactivity or over-responsiveness can make it more difficult to adapt to the diet restrictions recommended after surgery. Reduced psychological adaptability in stressful situations may make them more inclined to relapse into disturbed eating. Obese patients with ED and high neuroticism may have a more ‘‘psychological driven’’ obesity than patients without ED and high neuroticism. Their obesity can be understood in terms of poorer psychological functioning. A hypothesis to be tested in future research could be
e145 that the obese pre-surgery patients with eating disorders and high scores on neuroticism would have poorer outcome after bariatric surgery.
Subthreshold binge eating disorder (SBED) Patients indicating SBED reported more depression and neuroticism than those without any eating disorders. Moreover, they did not differ essentially with regard to depression and neuroticism from the patients indicating full scale eating disorders. Accordingly, the patients with SBED seem to be quite similar to those with full scale eating disorders on these variables. Prior studies have also found few differences in psychiatric symptom levels between the obese patients who binge eat and those with full scale BED [9,51,52]. In the present study, the patients with SBED did not show any more anxiety than the patients without ED symptoms. Moreover, the patients with subthreshold binge eating appear to be similar to those without eating disorders in regard to anxiety symptoms. This is not in accordance with a study of obese patients seeking weight-loss treatments other than surgery; the authors reported more anxiety symptoms in patients with binge eating [9]. Differences in instruments and patient populations, surgical patients versus non-surgery patients, may explain some of the discrepancy between the two studies. Finding more neuroticism in patients with SBED than in patients without eating disorders, but finding no differences between ED and SBED indicate new information about the severity of psychological problems in obese patients with SBED. The suggestion made by de Man Lapidoth et al. that patients with binge eating symptoms should be treated clinically as patients with EDs is supported by the present study. When diagnosing ED before weight-loss surgery, SBED should be incorporated into the assessments. Patients with SBED appear to be vulnerable to depression and neuroticism as those with ED.
Methodological considerations Studies reporting inter-correlations between HADS and EPQ-12 for ED were not found in the literature. Despite high inter-correlation between anxiety and neuroticism, the patients in the SBED group neither scored significantly higher on anxiety nor had more HADS-cases of anxiety than the patients without ED, while for neuroticism the SBED group had higher scores than those without ED. A limitation of the present study is related to the categorization of EDs based on the patients self-reports (EDO). Structured in-depth interviews
e146 like the Eating Disorder Examination (EDE) are considered to be the ‘‘gold standard’’ for diagnosing EDs [53]. Though a thorough interview-based psychiatric assessment is necessary to make clinical diagnoses, it is also rather time consuming. Accordingly, when ED is identified by self-reports, the results are to be interpreted with some caution. Prior research has shown that the use of self-report instruments can result in higher prevalence rates of eating disorders [54]. The EDO questionnaire used a supplementary definition of binge eating that may have helped the participants to respond more adequately. The same limitation applies to the classification of the HADS-cases. Nevertheless, correlations in the range of .62—.81 has been reported between the interview-based Montgomery Asberg Depression Rating Scale and the HADS-D scale [55] The incorporation of all the relevant eating disorders is a strength in the present study. It contributes a fairly detailed picture of both the eating disorders and the role of the subthreshold binge eating disorders. The good response rate and the low number of missing data are also strengths. Furthermore, the criteria used to select obese patients for surgery are in accordance with the National guidelines (Norwegian National Institutes of Health), which are rather similar to those used in other Scandinavian countries. The patients in the present study are therefore likely to be representative of the obese patients awaiting surgery in Scandinavia and are most likely similar to those of other Western countries.
Conclusions The findings of the present study indicate that obese patients with relevant eating disorders have more anxiety, depression, and neuroticism than obese patients without eating disorders. Interventions directed towards their psychological problems would probably benefit these patients. More information about how personality features such as neuroticism may interact with overeating and weight gain is warranted. Such knowledge could contribute to improved treatment and prevention. Our findings suggest that the obese patients with subthreshold binge eating disorders are quite like those with full-blown eating disorders in regards to their levels of neuroticism and depression, and that they are markedly different from those without any eating disorders. This suggests that patients with sub-threshold binge eating disorders should be identified and treated similar to those with EDs.
J.K. Dahl et al.
Conflict of interest No conflict of interest to declare.
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e147 [38] Zigmond AS, Snaith RP. The hospital anxiety and depression scale. Acta Psychiatr Scand 1983;67:361—70. [39] Olsson I, Mykletun A, Dahl AA. The hospital anxiety and depression rating scale: a cross-sectional study of psychometrics and case finding abilities in general practice. BMC Psychiatry 2005;5:46. [40] Eysenck H, Eysenck S. The manual for the Eysenck Personality Questionnaire. London: Hodder & Stoughton; 1975. [41] Eysenck HJ, Barret G, Wilson G, Jackson C. Primary trait measurement of the 21 components of the P-E-N system. Eur J Psychol Assess 1992;8: 109—17. [42] Rowland ML. Self-reported weight and height. Am J Clin Nutr 1990;52:1125—33. [43] Dekkers JC, van Wier MF, Hendriksen IJ, Twisk JW, van Mechelen W. Accuracy of self-reported body weight, height and waist circumference in a Dutch overweight working population. BMC Med Res Methodol 2008;8:69. [44] Cohen J. Statistical power analysis for the behavioral sciences. Second ed. New Jersey and London: Lawrence Erlbaum; 1988. [45] Rosenthal R, Rosnow RL. Essentials of behavioral research: methods and data analysis. Third ed. Boston: Mc-Graw Hill; 2008. [46] Rosenthal R, Rosnow RL, Rubin DB. Contrasts and effect sizes in behavioral research: a correlational approach. Cambridge: Cambridge University Press; 2000. [47] Gardner MJ, Altman DG. Confidence intervals rather than P values. In: Altman DG, Machin D, Bryant TN, Gardner MJ, editors. Statistics with confidence: confidence intervals and statistical guidelines. second ed. London: British Medical Journal; 2000. p. 15—27. [48] Newcombe RG, Altman DG. Proportions and their differences. In: Altman DG, Machin D, Bryant TN, Gardner MJ, editors. Statistics with confidence: confidence intervals and statistical guidelines. 2nd ed. London: British Medical Journal; 2000. [49] Hinkle DE, Wiersma W, Jurs SG. Applied statistics for the behavioural sciences. 2nd ed. Boston: Houghton Mifflin Comp.; 1988. [50] Canetti L, Berry EM, Elizur Y. Psychosocial predictors of weight loss and psychological adjustment following bariatric surgery and a weight-loss program: the mediating role of emotional eating. Int J Eat Disord 2009;42:109—17. [51] Friederich HC, Schild S, Wild B, de Zwaan M, Quenter A, Herzog W, et al. Treatment outcome in people with subthreshold compared with full-syndrome binge eating disorder. Obesity (Silver Spring) 2007;15:283—7. [52] Striegel-Moore RH, Dohm FA, Solomon EE, Fairburn CG, Pike KM, Wilfley DE. Subthreshold binge eating disorder. Int J Eat Disord 2000;27:270—8. [53] Cooper Z, Cooper PJ, Fairburn CG. The validity of the eating disorder examination and its subscales. Br J Psychiatry 1989;154:807—12. [54] Kalarchian MA, Wilson GT, Brolin RE, Bradley L. Assessment of eating disorders in bariatric surgery candidates: self-report questionnaire versus interview. Int J Eat Disord 2000;28:465—9. [55] Bjelland I, Dahl AA, Haug TT, Neckelmann D. The validity of the hospital anxiety and depression scale. An updated literature review. J Psychosom Res 2002;52:69—77.
Available online at www.sciencedirect.com
ORIGINAL ARTICLE
Depression, anxiety, and neuroticism in obese patients waiting for bariatric surgery: Differences between patients with and without eating disorders and subthreshold binge eating disorders Jens K. Dahl a,b,∗, Lasse Eriksen a,c, Einar Vedul-Kjelsås a,b, Magnus Strømmen a,d, Bård Kulseng d, Ronald Mårvik d, Are Holen a,e a
Department of Neuroscience, Faculty of Medicine, Norwegian University of Science and Technology NTNU, N-7006 Trondheim, Norway b Department of Research and Development, AFFU, St. Olavs University Hospital, Division of Psychiatry, Østmarka, N-7006 Trondheim, Norway c Department of Nidaros DPS, St. Olavs University Hospital, Division of Psychiatry, N-7440 Trondheim, Norway d Centre for Obesity, St. Olavs University Hospital, N-7006 Trondheim, Norway e Pain Care Unit, St. Olavs University Hospital, N-7006 Trondheim, Norway Received 23 March 2011 ; received in revised form 14 July 2011; accepted 18 July 2011
KEYWORDS Obesity; Eating disorders; Bariatric surgery; Neuroticism; Anxiety and depression
Summary Objective: This study investigated self-reported levels of depression, anxiety and neuroticism in obese patients waiting for bariatric surgery. The patients who indicated that they might have eating disorders (ED) or subthreshold binge eating disorders (SBED) were compared with those without. Method: The design was cross sectional. Obese patients (n = 160, 117 women, 43 men) returned self-report questionnaires: Eating Disorders in Obesity (EDO) indicated eating disorder status; Hospital Anxiety and Depression Scale (HADS) assessed symptoms and caseness of depression and anxiety; and the Eysenck Personality Questionnaire (EPQ-12) captured neuroticism. Age, BMI and gender were also recorded. Results: Patients with ED (n = 28) presented significantly higher levels of depression, anxiety and neuroticism as well as more HADS-cases for depression and anxiety than those without ED (n = 109). Patients with sub-diagnostic binge eating disorders (SBED, n = 23) also reported significantly more depression symptom levels, and number of HADS-cases of depression, than those without ED. In addition, the SBED group showed
∗ Corresponding author at: Department of Research and Development, St. Olavs University Hospital, Division of Psychiatry, P.O. Box 3008 Lade, N-7441 Trondheim, Norway. Tel.: +47 72 82 30 30; fax: +47 72 82 30 46. E-mail address: [email protected] (J.K. Dahl).
1871-403X/$ — see front matter © 2011 Asian Oceanian Association for the Study of Obesity. Published by Elsevier Ltd. All rights reserved.
doi:10.1016/j.orcp.2011.07.005
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J.K. Dahl et al. significantly more neuroticism than patients without ED. No significant differences were found between men and women, for high/low age, or for high/low BMI. Conclusion: The data displayed that obese pre-surgery patients with eating disorders have more psychological problems than those without. Patients with SBED were more similar to those with full scale eating disorders in their level of depression and neuroticism than those without ED. Clinically, obese patients with SBED should probably be regarded as those who have full scale ED. © 2011 Asian Oceanian Association for the Study of Obesity. Published by Elsevier Ltd. All rights reserved.
Introduction Approximately 50% of obese patients who sought bariatric surgery reported comorbid psychopathology that was in accordance with the DSM-IV criteria, Axis I [1,2]. Mood and anxiety disorders have been reported in about 20% [3,4] and Binge Eating Disorder (BED) has commonly been found in 16—30% of the obese patients who seek surgical weight loss treatment [5,6]. There are several reasons that eating disorders are of particular interest in the obese pre-surgery patients. Firstly, binge eating seems to induce obesity. Secondly, BED is assumed to negatively influence the outcome of the surgical procedures. Uncontrolled eating is not in accordance with the behavioral recommendations after bariatric surgery [6]. Thirdly, obese patients with eating disorders tend to have more psychiatric distress than those without eating disorders [4,7], which indicates a need for psychological treatment. Among the obese patients seeking surgery, three eating disorders are common: Bulimia Nervosa (BN), Eating Disorder Not Otherwise Specified (EDNOS), and the sub-category of EDNOS called Binge Eating Disorder (BED) presented in the appendix of DSM-IV-TR [8]. In the pre-surgery population, BED is the most studied [6]. The proposed diagnostic criteria for BED include episodes of binge eating, i.e., the intake of large amounts of food within 2 h, together with a sense of lost control over eating. BED is not associated with inappropriate compensatory behaviors, as is BN. The clinical relevance of low frequency binge eating or subthreshold eating disorders among patients seeking bariatric surgery has been debated. From a non-surgical obese sample, sub-diagnostic binge eating was associated with more psychiatric comorbidity [9]. According to one review article, sub-diagnostic binge eating is more prevalent than BED in patients seeking surgical treatment, the reported prevalence has varied from 6% to 64% [6]. Obese pre-surgery patients with eating disorders show Axis I comorbidity more often than those without eating disorders [10—12]. The diag-
nostic criteria for other psychiatric disorders are met among 66.7% of patients with eating disorders compared to 26.7% among those without eating disorders [4]. More concern about shape, weight and unfavorable treatment outcomes have been reported from binge eaters than from non-binge eaters [10—13]. Higher levels of self-reported psychiatric symptoms and lower quality of life in obese patients with binge eating disorders compared to patients without have been reported [14,15]. Accordingly, researchers have suggested that obese patients with eating disorders should be considered a separate diagnostic entity with specific needs in the weight-loss treatment [9,12,16]. Further investigation into the psychological functioning of obese patients with and without eating disorders seems warranted.
Personality traits Personality traits can be defined as: ‘‘enduring dimensions of individual differences in tendencies to show consistent patterns of thoughts, feelings, and actions’’ [17]. Efforts to find the ‘‘personality’’ of the morbidly obese have failed. However, some reports indicate that the morbidly obese have more personality problems than those in the general population [18,19]. One report concluded that the obese do not differ from the general population on non-weight-related personality traits [20]. In several other studies, associations between personality traits and eating disorders have been found [21,22]. The personality trait ‘‘neuroticism’’ is defined as the propensity to experience negative emotions [23]. It has consistently been recognized as one of the main dimensions of personality [24] and is captured by personality inventories such as Eysenck Personality Questionnaire (EPQ) and NEO Personality Inventory Revised (NEO PI-R) [25]. In the EPQ and NEO-PI-R questionnaires, neuroticism is represented by emotional instability, anxiousness, guilt feelings, low self-esteem, hypersensitivity, tension,
Depression, anxiety, and neuroticism in obese patients shyness, and emotionalism [23,26]. Positive associations between neuroticism and eating disorders have also been demonstrated [22,27,28], while the results regarding associations between neuroticism and obesity have been mixed [21,29,30]. High levels of neuroticism seem to increase body dissatisfaction and destructive eating behaviors [31]. Exposure to adverse life events can increase negative affects. In obese patients this may result in negative feelings about their appearance and instigate overeating. A literature search on obese pre-surgery patients revealed no prior investigations of patients with and without eating disorders that also included measures of neuroticism. Most studies on the associations between personality and eating disorders have focused on anorexia nervosa and bulimia nervosa [22]. Less research has been done on personality variables in patients who are prone to binge eating [22]. Previous studies concerning obese pre-surgery patients have exclusively studied the associations between BED or binge eating behavior and psychological distress [5,6,32]. Few studies have tried to distinguish between the eating disorders. In the present study, all the relevant DSM-IVTR eating disorder diagnoses were included. Two groups of obese patients, those indicating eating disorders and those indicating subthreshold binge eating disorders (SBED), were compared with patients without any eating disorders. They were contrasted with regard to depression, anxiety, neuroticism, and the occurrence of HADS-cases of depression and anxiety. In the explorative part of the study, depression, anxiety, and neuroticism were investigated in relation to age, BMI, and gender. The directional hypotheses were as follows: (1) Patients indicating eating disorders will report more depression, anxiety and neuroticism than those without eating disorders. (2) Patients indicating subthreshold binge eating disorders will report more depression, anxiety, and neuroticism than those without eating disorders.
Methods Participants, procedures, and design Questionnaires were mailed to 209 morbidly obese patients waiting for bariatric surgery at St. Olavs University Hospital, Norway. One reminder was sent by mail. In 2005, the participants gave their informed consent. The response rate was 76.5%;
e141 160 completed their questionnaires. Of the participants, 117 (73.1%) were women and 43 (26.9%) were men. Mean age and BMI for the total sample were, respectively, 41.1 (SD = 10.4) and 47.2 (SD = 5.8). For further descriptions of the patient characteristics, see Dahl et al. [33]. Their responses had no bearing upon the preoperative approval process. The inclusion criteria for gastric bypass surgery were: BMI (kg/m2 ) between 35 and 40 plus one obesity-related somatic comorbidity or BMI ≥ 40. Patients who fulfilled any of the following criteria were excluded: severe mental disorders except eating disorders, pregnancy, prior bariatric surgery, substance abuse, or dependence on a wheelchair or crutches. The study was cross-sectional and based on self-reports. Approval from the Regional Committee for Research Ethics in Central Norway was given for the study.
Assessments of eating disorders Eating Disorders in Obesity (EDO) is an 11-item self-report questionnaire designed to detect any type of eating disorder in obese populations [34]. The questionnaire was developed from the ‘‘Survey of the Eating Disorders’’ (SEDs) by Gotestam and Agras and is based on the DSM-IV criteria [35]. The EDO is an adjusted short version of the SEDs that excludes questions about anorectic symptoms as underweight is irrelevant for obese patients. For the sake of clarity, the questionnaire starts with a definition of binge eating. EDO has good test-retest reliability and validity in relation to EDE [36]. With a 14-day interval in a student sample, the testretest reliability showed complete convergence of the derived diagnoses between the first and second response to EDO [34]. In this study, the EDO was used to identify three eating disorder diagnoses: Bulimia Nervosa (BN, n = 1), Binge Eating Disorder (BED, n = 21), and Eating Disorder Not Otherwise Specified (EDNOS, n = 6). Those who fulfilled the criteria were regarded as indicating eating disorders (ED). Patients who were one criterion short of the BN diagnosis were considered as having EDNOS. Five of six patients in this category matched the description of EDNOS example 3 in the DSM-IV-TR: ‘‘All the criteria for Bulimia Nervosa are met except that the binge eating and inappropriate compensatory mechanisms occur at a frequency of less than twice a week or for a duration of less than 3 months’’ [8]. One patient, who lacked a criterion of the BN diagnosis other than what has been specified in example 3 in DSM-IV-TR (self-evaluation is unduly influenced by body shape and weight), was categorized as having EDNOS. This person was included since EDNOS originally was
e142 intended to serve as a residual category for eating disorders previously neglected by most researchers [37]. In addition, a subthreshold diagnostic group called Subthreshold binge eating disorder (SBED, n = 23) was included. The category was made by the authors and consisted of those who were one criterion short of the BED diagnosis. This entity is not part of the DSM manual, though at times it is reported as a specific category [16] or included in the BED diagnosis when more liberal criteria are applied [15]. The 160 patients were divided into three groups: Group 1 was ‘‘ED’’ (n = 28) and fulfilled the criteria of BN, EDNOS, or BED: Group 2 was called ‘‘SBED’’ (n = 23) and lacked one of the criteria for BED, namely Subthreshold binge eating disorder; and Group 3 was called ‘‘Not ED-SBED’’ (n = 109) as they were without any eating disorder (ED) and also without any subthreshold binge eating disorder. Group 1 and 2 were tested for Mean Differences in scores on the dependent variables against Group 3. In the present paper, the patients in Group 3 ‘‘Not ED-SBED’’ (n = 109) is referred to as ‘‘without eating disorders’’. Accordingly, the 23 patients with SBED are not included in the group called ‘‘without eating disorders’’.
Instruments Hospital Anxiety and Depression Scale (HADS) is a widely used self-report instrument for psychiatric distress [38]. The scale has 14 items that cover the last week. The two subscales, with seven items each, measure the person’s degree of depression (HADS-Depression) and anxiety (HADSAnxiety). Each item is scored from 0 to 3; higher scores represent higher levels of distress [38]. The clinically tested classification system developed for HADS considers a score of 0—7 on a sub-scale to be within the normal range, a score of 8—10 to be ‘‘a possible case’’, and a score of 11 or more to be a case of depression or anxiety [38]. In the present study, the criterion for a HADS-case of depression or anxiety was a score ≥11 for each scale, while Olssøn et al. applied a score of ≥8 [39]. Caseness indicates that a psychiatric diagnosis is quite likely. In the present study, the Cronbach’s alpha of HADSDepression was .75 and HADS-Anxiety was .84. Eysenck Personality Questionnaire (EPQ-12) is a twelve item self-report instrument derived from the EPQ 90-item version [40]. The EPQ-12 assesses the personality trait neuroticism [41]. Each item is rated as 1-‘yes’ or 0-‘no’. The potential score range is 0—12. In the present study, the Cronbach’s alpha of the EPQ-12 was .84.
J.K. Dahl et al. Information about age, BMI, and gender was also obtained. Studies have shown that overweight participants tend to underestimate their weight [42]. However, self-reported BMI seems to be fairly accurate when assessing the prevalence of overweight and obesity [43].
Statistics It is recommend that focused statistical tests are applied and that omnibus tests should be avoided [44—46]. In the present study, these recommendations were followed. Inferential statistics were applied by independent-samples t-tests (twotailed). Statistical tests were two-tailed in spite of the directional hypotheses since there is a close link between the use of the confidence interval and the two-sided hypothesis test (significance test) [47]. For the categorical variables, twotailed chi-squared tests with two samples (unpaired case, df = 1) were applied. Low numbers in some subgroups limited the statistical power; this is reflected in the wider confidence intervals. In the explorative part of the study, Pearson’s bivariate correlations (two-tailed) for continuous variables were applied. In addition, the dichotomous variables covering high/low age and high/low BMI were defined by the median split. Independent ttests were employed for the differences in anxiety, depression and neuroticism between patients with high/low age or high/low BMI and also between women and men. The alpha level was set to p ≤ .05 with exact p-values reported [46]. The t-test is not valid when the sample size of the two groups are too uneven and when the groups have significantly different variances [44,45]. The Mann—Whitney U Test was therefore applied for one comparison of the anxiety scores. For the t-test and chi-square tests, d and phi were calculated for the effect sizes. Cohen’s norms were applied for the effect sizes [44]. The confidence intervals for the proportions and their differences were computed with the recommended method in Newcombe and Altmann [48]. SPSS 16 for Windows was applied in the statistical analyses. There were missing responses in the EDO for two women and one man. It was impossible to diagnose their ED. The three participants were included in the data analyses as not having eating disorders. If one or more of the undiagnosed patients had an eating disorder or subthreshold binge eating disorder (SBED), this procedure would make it less likely to find significant differences between the groups. There were no missing responses in age, but four missing responses for BMI: the values were replaced by the groups mean BMI. There were 7
f
e
c
d
ED = Eating Disorder: Bulimia Nervosa (BN) + Binge Eating Disorder (BED) + Eating Disorder Not Otherwise Specified (EDNOS). SBED = Subthreshold Binge Eating Disorder (Respondents lacking one diagnostic criterion for BED). Not ED-SBED = Respondents with neither Eating Disorder nor Subthreshold Binge Eating Disorder. Depression and anxiety: Hospital Anxiety and Depression Scale (HADS). Neuroticism: Eysenck Personality Questionnaire (EPQ-12). Mann—Whitney U Test (two-tailed). a
HADS-Depression HADS-Anxiety Neuroticism
Neuroticisme
b
95% CI
[.087, 3.44] [−.22,3.56] [.33, 3.28] .48 .37 .55
d p
.039 .082 .017 130 130 128
df t
2.08 1.75 2.43 6.36 (3.70) 7.28 (4.00) 5.14 (3.22) 8.13 (3.62) 8.95 (4.84) 6.95 (3.30)
[1.11,3.80] .78 .001 133
Not ED-SBED n = 109 Mean (SD) SBEDb n = 23 Mean (SD)
3.62
[.77, 4.00] — .59 .18 .004 .032 135 —
95% CI d/r p df t/z
2.93 2.14f
6.36 (3.70) 7.28 (4.00) Median 7.00 5.14 (3.22) 8.75 (4.32) 9.46 (5.38) Median 10.50 7.60 (3.09) HADS-Depression HADS- Anxietyd
d
The patients with an indication of having ED reported significantly higher scores on the HADSDepression scale than the patients without ED, t (135) = 2.93, p = .004, d = .59, Mean Difference 2.38, 95% CI [.774, 4.00]. Patients indicating ED also reported significantly higher scores on the HADS-Anxiety scale than those without ED (Mann—Whitney U Test), z = 2.14, p = .032, r = .18. Moreover, the patients indicating ED had significantly higher scores on neuroticism than the patients without ED, t (133) = 3.62, p = .001, d = .78, Mean Difference 2.45, 95% CI [1.11, 3.80]. (See Table 1). Patients indicating SBED had significantly higher scores on HADS-Depression than patients without ED, t (130) = 2.08, p = .039, d = .48, Mean Difference 1.76, 95% CI [.087, 3.44]. No significant differences in HADS-Anxiety were found between patients in the SBED group and those without ED. The patients with SBED had significantly higher scores on neuroticism than the patients without ED, t (128) = 2.43, p = .017, d = .55, Mean Difference 1.81, 95% CI [.33, 3.28]. Subsequent analyses showed no significant differences between the patients diagnosed with ED and those categorized as SBED patients, with regards to scores on HADS-Depression, HADSAnxiety, and neuroticism. The number of HADS-cases with depression was significantly higher in the ED group and the SBED group than in the group of patients without eating disorders. Significantly more HADS-cases with anxiety were found among patients in the ED group, but not in the SBED group compared to patients without ED. Table 2 showed how the HADS-cases of depression and anxiety were distributed in the three categories of eating behaviors. In the subsequent analyses of the HADS-cases for depression and anxiety, no significant differences
Not ED-SBEDc n = 109 Mean (SD)
Results
e143
EDa n = 28 Mean (SD)
missing responses in the HADS-Depression, 5 in the HADS-Anxiety, and 18 in EPQ-12. In each of the three scales, the missing responses were replaced by mean scores. Patients with more than two missing responses were excluded from the data analyses [38]. For the HADS subscales, no patient had more than two missing responses. In the EPQ-12, three patients were excluded from the analyses due to missing endorsements. The remaining patients with missing responses on EPQ-12 were included in the analyses: one had two missing responses and 6 had one missing response.
Table 1 Comparisons between three groups of obese pre-surgery patients categorized according to their self-reported eating behaviors, their HADS-scores on depression and anxiety and their EPQ-12 score on neuroticism. The differences were computed by independent two-tailed t-tests or two-tailed Mann—Whitney U Test.
Depression, anxiety, and neuroticism in obese patients
[.029, .43] [−.019,.38]
95% CI
c
d
a
b
ED = Eating Disorder: Bulimia Nervosa (BN) + Binge Eating Disorder (BED) + Eating Disorder Not Otherwise Specified (EDNOS). SBED = Subthreshold Binge Eating Disorder (Respondents lacking one diagnostic criterion for BED). Not ED-SBED = Respondents with neither Eating Disorder nor Subthreshold Binge Eating Disorder. HADS-case = Patients with a score of 11 or more on HADS-Depression or HADS-Anxiety, indicates a case in need of further assessment and treatment.
.20 .15 .021 .085 5.35 2.97 %
17.43 20.18 19 24 39.13 39.13
HADS-casesd
Not ED-SBED n = 109
% HADS-casesd
9 9 HADS-Depression HADS-Anxiety
p 2
phi
.035 .003 4.46 8.70
SBEDb n = 23
%
17.43 20.18 19 24 35.71 50.00
HADS-casesd
Not ED-SBEDc n = 109
% HADS-casesd
10 14 HADS-Depression HADS-Anxiety
2
p
.18 .25
phi
95% CI
[.012, .38] [.086, .47]
J.K. Dahl et al.
EDa n = 28
Table 2 Obese patients waiting for bariatric surgery categorized into three groups according to self-reported eating behaviors. Differences in HADS-cases of depression and of anxiety within each group are displayed. (Chi-square tests, two samples, df = 1).
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were found between patients categorized with ED compared with those of the SBED group. In the explorative part of the study, no significant differences between men and women were found for the scores on HADS-Depression, or HADSAnxiety, or neuroticism. The same was true for patients with high versus low age, and high versus low BMI. Similarly, correlating HADS-Depression, HADS-Anxiety, and neuroticism with age and BMI gave correlations (two-tailed) from −.25 to .23. Likewise, no significant differences were found in the number of HADS-cases among men and women, or in the total sample between high and low age, or between high and low BMI. Among the 117 women, 28 HADS-cases of depression (23.93%) and 38 HADS-cases of anxiety (32.47%) were identified. There were 9 HADS-cases of depression (20.93%), and 9 HADS-cases of anxiety (20.93%) among the 43 men. In total, 37 of 160 patients (23.1%) qualified as HADS-cases of depression, and 47 patients of the 160 patients (29.4%) qualified as HADS-cases of anxiety. There were moderate positive correlations between HADS-Anxiety and HADS-Depression (r = .60, 36% shared variance), and between HADSDepression and neuroticism (r = .62, 38% shared variance). A high positive correlation between HADS-Anxiety and neuroticism (r = .78, 61% shared variance) was also found [49].
Discussion The findings support the hypothesis that those with eating disorders have more depression, anxiety and neuroticism than those without. The obese patients with ED also emerged with more HADS-cases for depression and for anxiety than those without. In addition, the findings suggest that patients with SBED report more depression and neuroticism and more HADS-cases of depression than patients without ED, which is in accordance with the hypothesis. According to Cohen’s norms [44], the effect sizes for the differences in depression and neuroticism between patients with and without eating disorders and between patients with SBED and without ED were almost moderate to almost large. This underscores the clinical relevance of the differences between patients with and without ED and SBED. In the explorative part of the study, no differences in anxiety, depression, or neuroticism were found between men and women, between patients with high/low age, or between high/low BMI. These variables are apparently unlikely to explain why
Depression, anxiety, and neuroticism in obese patients patients with eating disorders report more depression, anxiety, and neuroticism than those without. In the subsequent analysis between the patients with ED versus SBED, no differences were found in their levels of depression, anxiety, and neuroticism. The absence of significant differences between the groups may be due to low statistical power in the ttests. However, the p-values for depression, anxiety and neuroticism were .59, .73 and. 47. Accordingly, it seems unlikely that more participants in each group would have given different results in these comparisons. Hence, the data do not indicate that those with ED and SBED are essentially different on these parameters. Both when categorized as HADS-cases of depression or anxiety and when HADS was used as continuous variables, differences were found between those with and without eating disorders. The observation is strengthened by the differences found for neuroticism. Together these findings emphasize that there is a distinction between patients with eating disorders and patients without eating disorders. Patients with ED experience more psychological problems than those without eating disorders. The findings are in accordance with prior studies that showed more Axis I disorders and more psychiatric symptoms among the obese patients with eating disorders [9,14,27]. Patients with eating disorders appear to be more psychologically vulnerable, and thus, they seem to constitute a distinctive group within the obese population.
Neuroticism Patients indicating eating disorders (BN, BED, EDNOS), as well as those who indicated subthreshold binge eating disorders (SBED), displayed higher levels of neuroticism than those without ED. This is in accordance with a study by Bulik et al. [27]. The present findings suggest that more neurotic personalities are found among the obese patients with eating disorders. Resent research suggests that a neurotic predisposition, measured by NEOPI-R, restrains weight reduction and psychological adjustments after bariatric surgery [50]. Their emotional over-reactivity or over-responsiveness can make it more difficult to adapt to the diet restrictions recommended after surgery. Reduced psychological adaptability in stressful situations may make them more inclined to relapse into disturbed eating. Obese patients with ED and high neuroticism may have a more ‘‘psychological driven’’ obesity than patients without ED and high neuroticism. Their obesity can be understood in terms of poorer psychological functioning. A hypothesis to be tested in future research could be
e145 that the obese pre-surgery patients with eating disorders and high scores on neuroticism would have poorer outcome after bariatric surgery.
Subthreshold binge eating disorder (SBED) Patients indicating SBED reported more depression and neuroticism than those without any eating disorders. Moreover, they did not differ essentially with regard to depression and neuroticism from the patients indicating full scale eating disorders. Accordingly, the patients with SBED seem to be quite similar to those with full scale eating disorders on these variables. Prior studies have also found few differences in psychiatric symptom levels between the obese patients who binge eat and those with full scale BED [9,51,52]. In the present study, the patients with SBED did not show any more anxiety than the patients without ED symptoms. Moreover, the patients with subthreshold binge eating appear to be similar to those without eating disorders in regard to anxiety symptoms. This is not in accordance with a study of obese patients seeking weight-loss treatments other than surgery; the authors reported more anxiety symptoms in patients with binge eating [9]. Differences in instruments and patient populations, surgical patients versus non-surgery patients, may explain some of the discrepancy between the two studies. Finding more neuroticism in patients with SBED than in patients without eating disorders, but finding no differences between ED and SBED indicate new information about the severity of psychological problems in obese patients with SBED. The suggestion made by de Man Lapidoth et al. that patients with binge eating symptoms should be treated clinically as patients with EDs is supported by the present study. When diagnosing ED before weight-loss surgery, SBED should be incorporated into the assessments. Patients with SBED appear to be vulnerable to depression and neuroticism as those with ED.
Methodological considerations Studies reporting inter-correlations between HADS and EPQ-12 for ED were not found in the literature. Despite high inter-correlation between anxiety and neuroticism, the patients in the SBED group neither scored significantly higher on anxiety nor had more HADS-cases of anxiety than the patients without ED, while for neuroticism the SBED group had higher scores than those without ED. A limitation of the present study is related to the categorization of EDs based on the patients self-reports (EDO). Structured in-depth interviews
e146 like the Eating Disorder Examination (EDE) are considered to be the ‘‘gold standard’’ for diagnosing EDs [53]. Though a thorough interview-based psychiatric assessment is necessary to make clinical diagnoses, it is also rather time consuming. Accordingly, when ED is identified by self-reports, the results are to be interpreted with some caution. Prior research has shown that the use of self-report instruments can result in higher prevalence rates of eating disorders [54]. The EDO questionnaire used a supplementary definition of binge eating that may have helped the participants to respond more adequately. The same limitation applies to the classification of the HADS-cases. Nevertheless, correlations in the range of .62—.81 has been reported between the interview-based Montgomery Asberg Depression Rating Scale and the HADS-D scale [55] The incorporation of all the relevant eating disorders is a strength in the present study. It contributes a fairly detailed picture of both the eating disorders and the role of the subthreshold binge eating disorders. The good response rate and the low number of missing data are also strengths. Furthermore, the criteria used to select obese patients for surgery are in accordance with the National guidelines (Norwegian National Institutes of Health), which are rather similar to those used in other Scandinavian countries. The patients in the present study are therefore likely to be representative of the obese patients awaiting surgery in Scandinavia and are most likely similar to those of other Western countries.
Conclusions The findings of the present study indicate that obese patients with relevant eating disorders have more anxiety, depression, and neuroticism than obese patients without eating disorders. Interventions directed towards their psychological problems would probably benefit these patients. More information about how personality features such as neuroticism may interact with overeating and weight gain is warranted. Such knowledge could contribute to improved treatment and prevention. Our findings suggest that the obese patients with subthreshold binge eating disorders are quite like those with full-blown eating disorders in regards to their levels of neuroticism and depression, and that they are markedly different from those without any eating disorders. This suggests that patients with sub-threshold binge eating disorders should be identified and treated similar to those with EDs.
J.K. Dahl et al.
Conflict of interest No conflict of interest to declare.
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