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The Journal of Psychology: Interdisciplinary and Applied Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/vjrl20
Worry and Rumination in Generalized Anxiety Disorder and Obsessive Compulsive Disorder a
a
Kaiser A. Dar & Naved Iqbal a
Jamia Millia Islamia (A Central University) Published online: 13 Dec 2014.
Click for updates To cite this article: Kaiser A. Dar & Naved Iqbal (2014): Worry and Rumination in Generalized Anxiety Disorder and Obsessive Compulsive Disorder, The Journal of Psychology: Interdisciplinary and Applied, DOI: 10.1080/00223980.2014.986430 To link to this article: http://dx.doi.org/10.1080/00223980.2014.986430
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Worry and Rumination in Generalized Anxiety Disorder and Obsessive Compulsive Disorder KAISER A. DAR NAVED IQBAL Jamia Millia Islamia (A Central University)
ABSTRACT. Ample work has already been conducted on worry and rumination as negative thought processes involved in the etiology of most of the anxiety and mood related disorders. However, minimal effort has been exerted to investigate whether one type of negative thought process can make way for another type of negative thought process, and if so, how it subsequently results in experiencing a host of symptoms reflective of one or the other type of psychological distress. Therefore, the present study was taken up to investigate whether rumination mediates the relationship between worry and generalized anxiety disorder (GAD), and between worry and obsessive compulsive disorder (OCD) in two clinical groups. Self-report questionnaires tapping worry, rumination, generalized anxiety disorder (GAD), and obsessive compulsive disorder (OCD) were administered to a clinical sample of 60 patients aged 30–40. Worry, rumination, generalized anxiety disorder (GAD), and obsessive compulsive disorder (OCD) correlated substantially with each other, however, rumination did not mediate the relationship between worry and generalized anxiety disorder (GAD) and between worry and obsessive compulsive disorder (OCD). We also analyzed differences of outcome variables within two clinical groups. These results showed that worry and rumination were significantly different between GAD and OCD groups. Keywords: generalized anxiety disorder, obsessive compulsive disorder, rumination, worry
AMONG THE ANXIETY DISORDERS IN THE DSM-IV-TR (APA, 2000), two are defined primarily by excessive negatively-valenced cognitions: obsessive compulsive disorder (OCD) and generalized anxiety disorder (GAD) (Brown, Moras, Zinbarg, & Barlow, 1993). In OCD, excessive emotionally-valenced cognition can Address correspondence to Naved Iqbal, Department of Psychology, Jamia Millia Islamia (A Central University), Jamia Nagar, New Delhi, 110025, India; [email protected] (e-mail). Color versions of one or more of the figures in the article can be found online at www. tandfonline.com/ vjrl. 1
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be seen in obsessions, which are unwanted, repetitive thoughts considered inappropriate or harmful. Obsessional thoughts motivate compulsions, rigid behaviors performed ritualistically to undo harm related to obsessions (APA, 2000). In GAD, excessive anxiogenic cognition takes the form of perseverative worry, which consists of apprehensive thoughts about everyday concerns, such as finances, academic performance, and household maintenance (Burns, Keortge, Formea, & Sternberger, 1996). Perseverative worry sustains a high level of negative affect and physiological arousal, which may lead to tension, fatigue, and other somatic complaints (APA, 2000). Research examining the nature of these excessive cognitions supports their diagnostic specificity, as patients with OCD report more obsessional thoughts than patients with GAD, and patients with GAD report more perseverative worry than patients with OCD (Brown, Antony, & Barlow, 1992; Brown et al.). However, obsessional thoughts and perseverative worry often cooccur in clinical and nonclinical samples (Brown et al.; Clark & Claybourn, 1997). Indeed, self-report measures of obsessional thoughts and perseverative worry have been found to share a considerable degree of variance (Burns et al.; Freeston et al., 1994; Zinbarg & Barlow, 1996). Worry and rumination are cognitive processes characterized by thinking about personal concerns in unproductive, repetitive ways, and experiencing difficulties terminating these chains of thoughts (de Jong-Meyer, Beck, & Riede, 2009). Although rumination and worry overlap, they have distinguishing features (NolenHoeksema, Wisco, & Lyubomirsky, 2008). Rumination is thought to be past oriented while worrying is much more future oriented. Rumination is focused on issues of self-worth, meaning, and loss, whereas worry concerns anticipated threats. Where the conscious motive of ruminating is to gain insight in events, the motive to worry is to anticipate and prepare for threats. Finally, the nonconscious motive of rumination is to avoid aversive situations and the responsibility to take action, whereas for worry it is to avoid core negative affect and painful images. Thus far, worry has almost exclusively been studied in relation to anxiety, whereas rumination has been examined in relation to mood in general and unipolar depression in particular (Muris, Roelofs, Rassin, Franken, & Mayer, 2005). According to Borkovec (1994), worry is predominantly verbal activity that is reinforced because it enables individuals to avoid more emotionally arousing imagery-based processing of threatening information. It interferes with emotional processing and thus prevents the extinction of fear. Worried individuals prevent themselves from deploying their most adaptive coping resources, which contributes to the development and maintenance of anxiety (Borkovec). Despite the specificity of theories linking worry to anxiety and rumination to depression, recent research suggests that these links may not be so specific. Studies in adults (Fresco, Frankel, Mennin, Turk, & Heimberg, 2002; Muris et al., 2005) and children (Broeren, Muris, Bouwmeester, van der Heijden, & Abee, 2011) show that both rumination and worry correlate significantly with anxiety and depressive symptoms. Even when worry scores are partialed out of rumination and vice versa,
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worry and rumination are found to correlate significantly with depression and anxiety scores (Fresco et al.; Segerstrom, Tsao, Alden, & Craske, 2000). Exploratory factor analyses demonstrate that worry and rumination not only share substantial variance (Segerstrom et al., 2000), but also retain distinct characteristics (Fresco et al.; Muris, Roclofs, Meesters, & Boomsma, 2004). Rumination and worry items load on the same latent variable, namely repetitive thoughts (Segerstrom et al., 2000), but also on separate ‘Rumination’ and ‘Worry’ factors (Fresco et al.; Muris et al.). Consistent with these findings, Muris et al. (2004), in a study of adolescents, found worry to be a significant predictor of anxiety symptoms when controlling for rumination. However, unexpectedly they found that rumination was no longer a predictor of depressive symptoms after controlling for worry. Over the past decade, several studies have pointed to worry and rumination as negative thought processes that appear to be involved in the etiology and maintenance of spectrum of anxiety and mood disorders, specifically to generalized anxiety disorder (GAD) and major depressive disorder (MDD), respectively. However, insufficient attention has been devoted to how one negative thought process (e.g., worry) can give rise to another negative thought process (e.g., rumination), and which consequently leads to some psychological distress in the form of generalized anxiety disorder (GAD) and obsessive compulsive disorder (OCD). Thus, one of the goals of this study was to investigate the relationships between worry, rumination, generalized anxiety disorder (GAD), and obsessive compulsive disorder (OCD) in a clinical sample and we expected that worry and rumination would be related to both generalized anxiety disorder (GAD), and obsessive compulsive disorder (OCD). In line with results reported by Muris et al. (2004), we hypothesized that the relationship between worry and GAD as well as between worry and OCD would be mediated by rumination. Another purpose of this study was to investigate whether the repetitive thought (e.g., rumination) differently mediates the relationship between worry and generalized anxiety disorder (GAD), and between Worry and obsessive compulsive disorder, using a mediation model. Such a mediated relationship would suggest that worry would be related to generalized anxiety disorder (GAD), and obsessive compulsive disorder (OCD) differently through a repetitive thought (e.g., rumination). Method Participants Participants were recruited on an outpatient basis from the Government Psychiatric Diseases Hospital, Srinagar, from September to December, 2013. All the participants reported anxiety symptoms and were diagnosed by a licensed clinical psychologist using the Structured Clinical Interview for DSM-IV-TR disorders (SCID-I). Of the recruited 69 patients, 60 patients (37 were women and 23 men) satisfied the DSM-IV-TR assumptions for pure GAD and OCD. The clinical groups were composed of 27 participants with GAD, and 33 participants
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with OCD. Individuals suffering from comorbid disorders of any type and nature were excluded from participation so as to maintain the content specificity of DSM-IV-TR criteria. Participants ranged in age from 30 and 40 years, with a mean age of 35.7 years (standard deviation, SD = 9.4). The domicile composition was as follows: 31.67% urban, 23.33% rural, 16.67% semi-urban, and 11.67% semi-rural.
Procedure A full description of the study was rendered to the participants, and thereby a written informed consent was obtained from them. All the participants were assessed individually and asked to complete a battery of self-reported measures including those used in the present study. The questionnaires were filled by the participants in a conducive and congenial room of the Psychiatric Diseases Hospital, Srinagar, where the sample of the present study was taken. The first author of the study was available to answer the questions. However, most of the participants were able to complete the questionnaires without any help.
Measures Structured Clinical Interview for DSM-IV-TR The Structured Clinical Interview for DSM-IV-TR (SCID-I; Michael, Robert, Gibbon, & Williams, 2002) is a semi-structured interview for making major DSMIV-TR Axis 1 diagnoses. It is administered by a clinician or trained mental health professional who is familiar with the DSM-IV-TR classification and diagnostic criteria (APA, 2000). It is designed for use with subjects who are identified as psychiatric patients. The SCID-I is an ideal choice for research purpose due to its brevity and psychometrics (Lobbestael, Leurgans, & Arntz, 2010). Generalized Anxiety Disorder Questionnaire–IV The generalized anxiety disorder questionnaire (GADQ-IV; Newman et al., 2002) is a nine-item, Likert scale measure screening for GAD based on the DSMIV-TR diagnostic criteria. It has good psychometric properties, with specificity = .89, sensitivity = 145.83, and 2-week test-retest reliability = .92 (Newman et al.). The GADQ-IV is a good initial screening device for GAD—to tease out those not meeting DSM-IV-TR criteria and before a costlier structured is used for further assessment (Holmes & Newman, 2006). The scale measures excessiveness and uncontrollability of worry, and severity of related somatic symptoms. For scoring purposes, a cut off score of 5.7 has been the standard in assessing whether individuals have GAD, rather than matching responses (Newman et al.). In the current sample the measure demonstrated excellent to adequate internal consistency (Cronbach’s α = .80).
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Obsessive–Compulsive Inventory: Revised The obsessive compulsive inventory (OCI-R; Foa et al., 2002) is an 18-item self-report inventory that measures obsessive–compulsive symptom severity. Participants rate the degree to which they are bothered or distressed by OCD symptoms in the past month on a five–point scale from 0 (not at all) to 4 (extremely). The OCI-R assesses a range of OCD symptomatology including washing, checking/doubting, obsessing, mental neutralizing, ordering, and hoarding. The OCI-R demonstrates good psychometric properties (Foa et al.; Hajcak, Huppert, Simons, & Foa, 2004). In the present sample, Cronbach’s α of .93 was observed for OCI-R. Penn State Worry Questionnaire The Penn State Worry Questionnaire (PSWQ; Meyer, Miller, Metzger, & Borkovec, 1990) is a 16-item inventory and is most frequently used to asses pathological worry in both clinical and nonclinical populations. The PSWQ is designed to measure the generality, excessiveness, and uncontrollability of pathological worry. It has high internal consistency and good test–retest reliability .Items included in PSWQ is rated on 1–5 point scale. In the present study, the PSWQ demonstrated adequate internal consistency (Cronbach’s α = .95) Ruminative Response Scale The ruminative response scale (RSS; Nolen-Hoeksema & Morrow, 1991) is a 22–item scale that assesses an individual’s trait, or inherent levels of rumination. Items are rated on a 4-point scale (almost never to almost always) for the extent to which they reflect respondents’ thoughts or actions when feeling sad, down or depressed. The RRS consists of items measuring how often people engage in responses that are self- focused (e.g., “Think ‘why am I the only person with these problems”’), symptom-focused (e.g., “focus on the fact that I am always tired”), and focused on the causes and consequences of having a depressed mood (e.g., “think ‘I won’t be able to do my job/work because I feel so badly”’). The RRS has demonstrated a good 5–month test-retest reliability (r = .80, Nolen-Hoeksema, Parker, & Larson, 1994) as well as high internal consistency (α = .89) and validity in terms of predicting depression (Nolen-Hoeksema & Morrow, 1991). In the present study a Cronbach’s alpha of .87 was observed for RRS. Data Analysis Although normality of the sampling distribution was questionable due to our small sample size, normality was validated through the Shafiro–Wilk test. Thus, parametric statistics were applied in this study. Continuous variables are expressed as mean (SD), and the scores given in this study are sum scores of single items. Pearson’s correlation analysis was used to investigate relationships between outcome variables and group comparisons were analyzed by independent samples t-test and Cohen’s (d) was also applied to examine the strength of difference
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between the groups. The hypothesized mediation model was assessed with SPSS16 by causal steps method developed by Baron and Kenny (1986). This is the most commonly used and most frequently cited test of mediation in psychology. To test the significance of indirect effect Sobel test was used because the utility and performance of the test has been discussed and demonstrated frequently (Hoyle & Kenny, 1999; MacKinnon, 1994; MacKinnon & Dwyer, 1993; MacKinnon et al., 2001; MacKinnon, Warsi, & Dwyer, 1995; Stone & Sobel, 1990). MacKinnon, Lockwood, Hoffman, West, and Sheets (2002), in their comparison of 14 methods of assessing mediation effects, settle on the Sobel test (and its variants) as superior in terms of power and intuitive appeal. In the case of simple mediation, the Sobel test is conducted by comparing the strength of the indirect effect of X on Y to the point null hypothesis that it equals zero. The indirect effect of X on Y in this situation is defined as the product of the X→M path (a) and the M→Y path (b), or ab. In most situations, ab = (c – c ), where c is the simple (i.e., total) effect of X on Y, not controlling for M, and c is the X→Y path coefficient after the addition of M to the model. Standard errors of a and b are represented, respectively, by sa and sb . The standard error of the indirect effect (Sab ) is provided by Aroian (1944); Mood, Graybill, and Boes (1974); and Sobel (1982) as Sab =
b2 sa2 + a 2 sb2 + sa2 sb2
In order to conduct the test, ab is divided by sab to yield a critical ratio that is traditionally compared with the critical value from the standard normal distribution appropriate for a given alpha level. The rough critical value for the two-tailed version of the test, assuming that the sampling distribution of ab is normal and that α = .05, is ± 1.96. Results Descriptive Statistics Descriptive statistics for each variable are presented in Table 1. To estimate the differences of variables, an independent samples t test was conducted on GADQ-IV, OCI-R, PSWQ, and RRS within two groups (GAD and OCD). The results of this test indicated that there was a significant difference in GADQ-IV between the two groups, t(58) = 8.15, p < .001. These results suggest that the individuals in GAD group (M = 14.00; SD = 2.77) were more reflective of GADQ-IV features than individuals in the OCD group (M = 9.23; SD = 1.61). The size of this effect (d = 1.92), as indexed by Cohen’s (1988) coefficient, was found to exceed the convention for a large effect size (d = .80; Table 1). Significant difference was also found between the two groups on OCI-R, t(58) = 11.53, p < .001. The participants in OCD group (M = 40.23; SD = 5.01)
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TABLE 1. Means and Standard Deviations of All the Scales for the Total Sample and for GAD and OCD Separately
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Total sample GAD OCD Mean (SD) (N = 60) Mean (SD) (n = 30) Mean (SD) (n = 30) GAD–IV OCI–R PSWQ RRS
11.62 (3.29) 33.67 (7.94) 39.40 (5.78) 48.42 (5.04)
14.00 (2.77) 27.10 (3.71) 42.10 (5.60) 46.27 (3.66)
9.23 (1.61) 40.23 (5.01) 36.70 (4.62) 50.57 (5.36)
t
p
(d)
8.15 11.53 4.07 3.63
.000 .000 .000 .001
1.92 2.98 1.05 0.94
Note. GADQ–IV = generalized anxiety disorder questionnaire for DSM–IV; OIC–R = obsessive compulsive inventory–revised; PSWQ = Penn State worry questionnaire; RSS = ruminative response scale. d = Cohen’s (1988) convention for effect size; small: d ≥ 0.20; medium: d ≥ 0.50; large: d ≥ 0.80 effects.
scored higher than their counterparts in the GAD group (M = 27.10; SD = 3.71). The size of this effect (d = 2.98) was also found to exceed the convention for a large effect size (d = .80; Table 1). The two groups also showed significant difference on PSWQ, t(58) = 4.07, p < .001. These results suggest that that the individuals in GAD group (M = 42.10; SD = 5.60) were found more worrying than the individuals in the OCD group (M = 36.70; SD = 4.62). The size of this effect (d = 1.05) was again found to exceed the convention for a large effect size (d = .80; Table 1). The results also indicated that there was a significant difference in RRS between the two groups, t(58) = 3.63, p < .001. Therefore, these results suggest that the participants in OCD group (M = 50.57; SD = 5.36) were found more ruminating than their counterparts in the GAD group (M = 46.27; SD = 3.66). The size of this effect (d = 0.94) was also found to exceed the convention for a large effect size (d = .80; Table 1).
Correlations Correlational analyses were used to examine the differential relationships between worry (PSWQ), and rumination (RRS), as well as between generalized anxiety disorder (GADQ-IV) and obsessive compulsive disorder (OCI-R). As indicated in Table 2, worry (PSWQ) correlated with both generalized anxiety disorder (GAD) and obsessive-compulsive disorder (OCD). As expected, worry and rumination were also correlated. Generalized anxiety disorder (GAD) and obsessive-compulsive disorder (OCD) also showed significant correlation.
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TABLE 2. Zero-Order Correlation Between the Self-Report Measures (N = 60)
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1. GAD–IV 2. OIC–R 3. PSWQ 4. RRS
1
2
3
4
.80 — — —
.69∗∗ .93 — —
.37∗∗ .41∗∗ .95 —
.35∗∗ .26∗ .28∗ .87
Note. GADQ–IV = generalized anxiety disorder questionnaire for DSM–IV; OCI–R = obsessive compulsive inventory–revised; PSWQ = Penn State worry questionnaire; RRS = ruminative response scale; Numbers along the diagonal are internal consistencies of the scales. ∗ p < 0.05. ∗∗ p < 0.01 (two tailed).
Mediation Analyses Characterization of Mediators and Mediation A variable is said to mediate the relationship between a predictor variable and an outcome (criterion) variable if the predictor variable first has an effect on the mediator variable, and this in turn influences the outcome variable. Hence, a mediator (M) accounts for the relationship between a predictor variable (X) and the outcome variable (Y). • Complete mediation exists if the predictor variable exerts its total influence via the mediating variable (M). • Partial mediation is given if the predictor variable exerts some of its influence via M, and it also exerts some of its influence directly on the outcome variable and not via M. Two mediation analyses were performed by using the guidelines of Judd and Kenny (1981), and Baron and Kenny (1986) to test whether the relationship between worry and generalized anxiety disorder, and the relationship between worry and obsessive compulsive disorder are mediated by rumination. First, we tested whether the relationship between worry and generalized anxiety disorder was mediated by rumination. The estimates of 95% CIs and summary of mediation analyses are presented in Table 3 and Figure 1. The total and direct effects of worry on generalized anxiety disorder were β = .37, p < .01, and β = .30, p < .05. The difference between the total and direct effects was the total indirect effect through the proposed mediator, with a point estimate of .075 and a 95% confidence interval of –.01105, .02740. Because zero is in the 95% confidence interval, we can conclude that rumination does not mediate the worry–GAD relationship.
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TABLE 3. Indirect Effect of Worry on Generalized Anxiety Disorder (GAD) Through Rumination (N = 60) 95% Confidence Interval
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Point estimate Z-value Std. Error Sig. (two-tailed) Sobel
0.075
1.557
0.027
0.12
Lower
Upper
−.01105 .02740
Second, we investigated whether the relationship between worry and obsessive compulsive disorder was mediated by rumination. The estimate of 95% CI and summary of mediation analyses are presented in Table 4 and Figure 2. The total and direct effects of worry on obsessive compulsive disorder were significant (β = .41, p < .01; β = .37, p
The Journal of Psychology: Interdisciplinary and Applied Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/vjrl20
Worry and Rumination in Generalized Anxiety Disorder and Obsessive Compulsive Disorder a
a
Kaiser A. Dar & Naved Iqbal a
Jamia Millia Islamia (A Central University) Published online: 13 Dec 2014.
Click for updates To cite this article: Kaiser A. Dar & Naved Iqbal (2014): Worry and Rumination in Generalized Anxiety Disorder and Obsessive Compulsive Disorder, The Journal of Psychology: Interdisciplinary and Applied, DOI: 10.1080/00223980.2014.986430 To link to this article: http://dx.doi.org/10.1080/00223980.2014.986430
PLEASE SCROLL DOWN FOR ARTICLE Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages,
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This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. Terms & Conditions of access and use can be found at http://www.tandfonline.com/page/terms-and-conditions
The Journal of Psychology, 2015, 0(0), 1–15 C 2015 Taylor & Francis Group, LLC Copyright doi: 10.1080/00223980.2014.986430
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Worry and Rumination in Generalized Anxiety Disorder and Obsessive Compulsive Disorder KAISER A. DAR NAVED IQBAL Jamia Millia Islamia (A Central University)
ABSTRACT. Ample work has already been conducted on worry and rumination as negative thought processes involved in the etiology of most of the anxiety and mood related disorders. However, minimal effort has been exerted to investigate whether one type of negative thought process can make way for another type of negative thought process, and if so, how it subsequently results in experiencing a host of symptoms reflective of one or the other type of psychological distress. Therefore, the present study was taken up to investigate whether rumination mediates the relationship between worry and generalized anxiety disorder (GAD), and between worry and obsessive compulsive disorder (OCD) in two clinical groups. Self-report questionnaires tapping worry, rumination, generalized anxiety disorder (GAD), and obsessive compulsive disorder (OCD) were administered to a clinical sample of 60 patients aged 30–40. Worry, rumination, generalized anxiety disorder (GAD), and obsessive compulsive disorder (OCD) correlated substantially with each other, however, rumination did not mediate the relationship between worry and generalized anxiety disorder (GAD) and between worry and obsessive compulsive disorder (OCD). We also analyzed differences of outcome variables within two clinical groups. These results showed that worry and rumination were significantly different between GAD and OCD groups. Keywords: generalized anxiety disorder, obsessive compulsive disorder, rumination, worry
AMONG THE ANXIETY DISORDERS IN THE DSM-IV-TR (APA, 2000), two are defined primarily by excessive negatively-valenced cognitions: obsessive compulsive disorder (OCD) and generalized anxiety disorder (GAD) (Brown, Moras, Zinbarg, & Barlow, 1993). In OCD, excessive emotionally-valenced cognition can Address correspondence to Naved Iqbal, Department of Psychology, Jamia Millia Islamia (A Central University), Jamia Nagar, New Delhi, 110025, India; [email protected] (e-mail). Color versions of one or more of the figures in the article can be found online at www. tandfonline.com/ vjrl. 1
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be seen in obsessions, which are unwanted, repetitive thoughts considered inappropriate or harmful. Obsessional thoughts motivate compulsions, rigid behaviors performed ritualistically to undo harm related to obsessions (APA, 2000). In GAD, excessive anxiogenic cognition takes the form of perseverative worry, which consists of apprehensive thoughts about everyday concerns, such as finances, academic performance, and household maintenance (Burns, Keortge, Formea, & Sternberger, 1996). Perseverative worry sustains a high level of negative affect and physiological arousal, which may lead to tension, fatigue, and other somatic complaints (APA, 2000). Research examining the nature of these excessive cognitions supports their diagnostic specificity, as patients with OCD report more obsessional thoughts than patients with GAD, and patients with GAD report more perseverative worry than patients with OCD (Brown, Antony, & Barlow, 1992; Brown et al.). However, obsessional thoughts and perseverative worry often cooccur in clinical and nonclinical samples (Brown et al.; Clark & Claybourn, 1997). Indeed, self-report measures of obsessional thoughts and perseverative worry have been found to share a considerable degree of variance (Burns et al.; Freeston et al., 1994; Zinbarg & Barlow, 1996). Worry and rumination are cognitive processes characterized by thinking about personal concerns in unproductive, repetitive ways, and experiencing difficulties terminating these chains of thoughts (de Jong-Meyer, Beck, & Riede, 2009). Although rumination and worry overlap, they have distinguishing features (NolenHoeksema, Wisco, & Lyubomirsky, 2008). Rumination is thought to be past oriented while worrying is much more future oriented. Rumination is focused on issues of self-worth, meaning, and loss, whereas worry concerns anticipated threats. Where the conscious motive of ruminating is to gain insight in events, the motive to worry is to anticipate and prepare for threats. Finally, the nonconscious motive of rumination is to avoid aversive situations and the responsibility to take action, whereas for worry it is to avoid core negative affect and painful images. Thus far, worry has almost exclusively been studied in relation to anxiety, whereas rumination has been examined in relation to mood in general and unipolar depression in particular (Muris, Roelofs, Rassin, Franken, & Mayer, 2005). According to Borkovec (1994), worry is predominantly verbal activity that is reinforced because it enables individuals to avoid more emotionally arousing imagery-based processing of threatening information. It interferes with emotional processing and thus prevents the extinction of fear. Worried individuals prevent themselves from deploying their most adaptive coping resources, which contributes to the development and maintenance of anxiety (Borkovec). Despite the specificity of theories linking worry to anxiety and rumination to depression, recent research suggests that these links may not be so specific. Studies in adults (Fresco, Frankel, Mennin, Turk, & Heimberg, 2002; Muris et al., 2005) and children (Broeren, Muris, Bouwmeester, van der Heijden, & Abee, 2011) show that both rumination and worry correlate significantly with anxiety and depressive symptoms. Even when worry scores are partialed out of rumination and vice versa,
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worry and rumination are found to correlate significantly with depression and anxiety scores (Fresco et al.; Segerstrom, Tsao, Alden, & Craske, 2000). Exploratory factor analyses demonstrate that worry and rumination not only share substantial variance (Segerstrom et al., 2000), but also retain distinct characteristics (Fresco et al.; Muris, Roclofs, Meesters, & Boomsma, 2004). Rumination and worry items load on the same latent variable, namely repetitive thoughts (Segerstrom et al., 2000), but also on separate ‘Rumination’ and ‘Worry’ factors (Fresco et al.; Muris et al.). Consistent with these findings, Muris et al. (2004), in a study of adolescents, found worry to be a significant predictor of anxiety symptoms when controlling for rumination. However, unexpectedly they found that rumination was no longer a predictor of depressive symptoms after controlling for worry. Over the past decade, several studies have pointed to worry and rumination as negative thought processes that appear to be involved in the etiology and maintenance of spectrum of anxiety and mood disorders, specifically to generalized anxiety disorder (GAD) and major depressive disorder (MDD), respectively. However, insufficient attention has been devoted to how one negative thought process (e.g., worry) can give rise to another negative thought process (e.g., rumination), and which consequently leads to some psychological distress in the form of generalized anxiety disorder (GAD) and obsessive compulsive disorder (OCD). Thus, one of the goals of this study was to investigate the relationships between worry, rumination, generalized anxiety disorder (GAD), and obsessive compulsive disorder (OCD) in a clinical sample and we expected that worry and rumination would be related to both generalized anxiety disorder (GAD), and obsessive compulsive disorder (OCD). In line with results reported by Muris et al. (2004), we hypothesized that the relationship between worry and GAD as well as between worry and OCD would be mediated by rumination. Another purpose of this study was to investigate whether the repetitive thought (e.g., rumination) differently mediates the relationship between worry and generalized anxiety disorder (GAD), and between Worry and obsessive compulsive disorder, using a mediation model. Such a mediated relationship would suggest that worry would be related to generalized anxiety disorder (GAD), and obsessive compulsive disorder (OCD) differently through a repetitive thought (e.g., rumination). Method Participants Participants were recruited on an outpatient basis from the Government Psychiatric Diseases Hospital, Srinagar, from September to December, 2013. All the participants reported anxiety symptoms and were diagnosed by a licensed clinical psychologist using the Structured Clinical Interview for DSM-IV-TR disorders (SCID-I). Of the recruited 69 patients, 60 patients (37 were women and 23 men) satisfied the DSM-IV-TR assumptions for pure GAD and OCD. The clinical groups were composed of 27 participants with GAD, and 33 participants
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with OCD. Individuals suffering from comorbid disorders of any type and nature were excluded from participation so as to maintain the content specificity of DSM-IV-TR criteria. Participants ranged in age from 30 and 40 years, with a mean age of 35.7 years (standard deviation, SD = 9.4). The domicile composition was as follows: 31.67% urban, 23.33% rural, 16.67% semi-urban, and 11.67% semi-rural.
Procedure A full description of the study was rendered to the participants, and thereby a written informed consent was obtained from them. All the participants were assessed individually and asked to complete a battery of self-reported measures including those used in the present study. The questionnaires were filled by the participants in a conducive and congenial room of the Psychiatric Diseases Hospital, Srinagar, where the sample of the present study was taken. The first author of the study was available to answer the questions. However, most of the participants were able to complete the questionnaires without any help.
Measures Structured Clinical Interview for DSM-IV-TR The Structured Clinical Interview for DSM-IV-TR (SCID-I; Michael, Robert, Gibbon, & Williams, 2002) is a semi-structured interview for making major DSMIV-TR Axis 1 diagnoses. It is administered by a clinician or trained mental health professional who is familiar with the DSM-IV-TR classification and diagnostic criteria (APA, 2000). It is designed for use with subjects who are identified as psychiatric patients. The SCID-I is an ideal choice for research purpose due to its brevity and psychometrics (Lobbestael, Leurgans, & Arntz, 2010). Generalized Anxiety Disorder Questionnaire–IV The generalized anxiety disorder questionnaire (GADQ-IV; Newman et al., 2002) is a nine-item, Likert scale measure screening for GAD based on the DSMIV-TR diagnostic criteria. It has good psychometric properties, with specificity = .89, sensitivity = 145.83, and 2-week test-retest reliability = .92 (Newman et al.). The GADQ-IV is a good initial screening device for GAD—to tease out those not meeting DSM-IV-TR criteria and before a costlier structured is used for further assessment (Holmes & Newman, 2006). The scale measures excessiveness and uncontrollability of worry, and severity of related somatic symptoms. For scoring purposes, a cut off score of 5.7 has been the standard in assessing whether individuals have GAD, rather than matching responses (Newman et al.). In the current sample the measure demonstrated excellent to adequate internal consistency (Cronbach’s α = .80).
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Obsessive–Compulsive Inventory: Revised The obsessive compulsive inventory (OCI-R; Foa et al., 2002) is an 18-item self-report inventory that measures obsessive–compulsive symptom severity. Participants rate the degree to which they are bothered or distressed by OCD symptoms in the past month on a five–point scale from 0 (not at all) to 4 (extremely). The OCI-R assesses a range of OCD symptomatology including washing, checking/doubting, obsessing, mental neutralizing, ordering, and hoarding. The OCI-R demonstrates good psychometric properties (Foa et al.; Hajcak, Huppert, Simons, & Foa, 2004). In the present sample, Cronbach’s α of .93 was observed for OCI-R. Penn State Worry Questionnaire The Penn State Worry Questionnaire (PSWQ; Meyer, Miller, Metzger, & Borkovec, 1990) is a 16-item inventory and is most frequently used to asses pathological worry in both clinical and nonclinical populations. The PSWQ is designed to measure the generality, excessiveness, and uncontrollability of pathological worry. It has high internal consistency and good test–retest reliability .Items included in PSWQ is rated on 1–5 point scale. In the present study, the PSWQ demonstrated adequate internal consistency (Cronbach’s α = .95) Ruminative Response Scale The ruminative response scale (RSS; Nolen-Hoeksema & Morrow, 1991) is a 22–item scale that assesses an individual’s trait, or inherent levels of rumination. Items are rated on a 4-point scale (almost never to almost always) for the extent to which they reflect respondents’ thoughts or actions when feeling sad, down or depressed. The RRS consists of items measuring how often people engage in responses that are self- focused (e.g., “Think ‘why am I the only person with these problems”’), symptom-focused (e.g., “focus on the fact that I am always tired”), and focused on the causes and consequences of having a depressed mood (e.g., “think ‘I won’t be able to do my job/work because I feel so badly”’). The RRS has demonstrated a good 5–month test-retest reliability (r = .80, Nolen-Hoeksema, Parker, & Larson, 1994) as well as high internal consistency (α = .89) and validity in terms of predicting depression (Nolen-Hoeksema & Morrow, 1991). In the present study a Cronbach’s alpha of .87 was observed for RRS. Data Analysis Although normality of the sampling distribution was questionable due to our small sample size, normality was validated through the Shafiro–Wilk test. Thus, parametric statistics were applied in this study. Continuous variables are expressed as mean (SD), and the scores given in this study are sum scores of single items. Pearson’s correlation analysis was used to investigate relationships between outcome variables and group comparisons were analyzed by independent samples t-test and Cohen’s (d) was also applied to examine the strength of difference
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between the groups. The hypothesized mediation model was assessed with SPSS16 by causal steps method developed by Baron and Kenny (1986). This is the most commonly used and most frequently cited test of mediation in psychology. To test the significance of indirect effect Sobel test was used because the utility and performance of the test has been discussed and demonstrated frequently (Hoyle & Kenny, 1999; MacKinnon, 1994; MacKinnon & Dwyer, 1993; MacKinnon et al., 2001; MacKinnon, Warsi, & Dwyer, 1995; Stone & Sobel, 1990). MacKinnon, Lockwood, Hoffman, West, and Sheets (2002), in their comparison of 14 methods of assessing mediation effects, settle on the Sobel test (and its variants) as superior in terms of power and intuitive appeal. In the case of simple mediation, the Sobel test is conducted by comparing the strength of the indirect effect of X on Y to the point null hypothesis that it equals zero. The indirect effect of X on Y in this situation is defined as the product of the X→M path (a) and the M→Y path (b), or ab. In most situations, ab = (c – c ), where c is the simple (i.e., total) effect of X on Y, not controlling for M, and c is the X→Y path coefficient after the addition of M to the model. Standard errors of a and b are represented, respectively, by sa and sb . The standard error of the indirect effect (Sab ) is provided by Aroian (1944); Mood, Graybill, and Boes (1974); and Sobel (1982) as Sab =
b2 sa2 + a 2 sb2 + sa2 sb2
In order to conduct the test, ab is divided by sab to yield a critical ratio that is traditionally compared with the critical value from the standard normal distribution appropriate for a given alpha level. The rough critical value for the two-tailed version of the test, assuming that the sampling distribution of ab is normal and that α = .05, is ± 1.96. Results Descriptive Statistics Descriptive statistics for each variable are presented in Table 1. To estimate the differences of variables, an independent samples t test was conducted on GADQ-IV, OCI-R, PSWQ, and RRS within two groups (GAD and OCD). The results of this test indicated that there was a significant difference in GADQ-IV between the two groups, t(58) = 8.15, p < .001. These results suggest that the individuals in GAD group (M = 14.00; SD = 2.77) were more reflective of GADQ-IV features than individuals in the OCD group (M = 9.23; SD = 1.61). The size of this effect (d = 1.92), as indexed by Cohen’s (1988) coefficient, was found to exceed the convention for a large effect size (d = .80; Table 1). Significant difference was also found between the two groups on OCI-R, t(58) = 11.53, p < .001. The participants in OCD group (M = 40.23; SD = 5.01)
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TABLE 1. Means and Standard Deviations of All the Scales for the Total Sample and for GAD and OCD Separately
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Total sample GAD OCD Mean (SD) (N = 60) Mean (SD) (n = 30) Mean (SD) (n = 30) GAD–IV OCI–R PSWQ RRS
11.62 (3.29) 33.67 (7.94) 39.40 (5.78) 48.42 (5.04)
14.00 (2.77) 27.10 (3.71) 42.10 (5.60) 46.27 (3.66)
9.23 (1.61) 40.23 (5.01) 36.70 (4.62) 50.57 (5.36)
t
p
(d)
8.15 11.53 4.07 3.63
.000 .000 .000 .001
1.92 2.98 1.05 0.94
Note. GADQ–IV = generalized anxiety disorder questionnaire for DSM–IV; OIC–R = obsessive compulsive inventory–revised; PSWQ = Penn State worry questionnaire; RSS = ruminative response scale. d = Cohen’s (1988) convention for effect size; small: d ≥ 0.20; medium: d ≥ 0.50; large: d ≥ 0.80 effects.
scored higher than their counterparts in the GAD group (M = 27.10; SD = 3.71). The size of this effect (d = 2.98) was also found to exceed the convention for a large effect size (d = .80; Table 1). The two groups also showed significant difference on PSWQ, t(58) = 4.07, p < .001. These results suggest that that the individuals in GAD group (M = 42.10; SD = 5.60) were found more worrying than the individuals in the OCD group (M = 36.70; SD = 4.62). The size of this effect (d = 1.05) was again found to exceed the convention for a large effect size (d = .80; Table 1). The results also indicated that there was a significant difference in RRS between the two groups, t(58) = 3.63, p < .001. Therefore, these results suggest that the participants in OCD group (M = 50.57; SD = 5.36) were found more ruminating than their counterparts in the GAD group (M = 46.27; SD = 3.66). The size of this effect (d = 0.94) was also found to exceed the convention for a large effect size (d = .80; Table 1).
Correlations Correlational analyses were used to examine the differential relationships between worry (PSWQ), and rumination (RRS), as well as between generalized anxiety disorder (GADQ-IV) and obsessive compulsive disorder (OCI-R). As indicated in Table 2, worry (PSWQ) correlated with both generalized anxiety disorder (GAD) and obsessive-compulsive disorder (OCD). As expected, worry and rumination were also correlated. Generalized anxiety disorder (GAD) and obsessive-compulsive disorder (OCD) also showed significant correlation.
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TABLE 2. Zero-Order Correlation Between the Self-Report Measures (N = 60)
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1. GAD–IV 2. OIC–R 3. PSWQ 4. RRS
1
2
3
4
.80 — — —
.69∗∗ .93 — —
.37∗∗ .41∗∗ .95 —
.35∗∗ .26∗ .28∗ .87
Note. GADQ–IV = generalized anxiety disorder questionnaire for DSM–IV; OCI–R = obsessive compulsive inventory–revised; PSWQ = Penn State worry questionnaire; RRS = ruminative response scale; Numbers along the diagonal are internal consistencies of the scales. ∗ p < 0.05. ∗∗ p < 0.01 (two tailed).
Mediation Analyses Characterization of Mediators and Mediation A variable is said to mediate the relationship between a predictor variable and an outcome (criterion) variable if the predictor variable first has an effect on the mediator variable, and this in turn influences the outcome variable. Hence, a mediator (M) accounts for the relationship between a predictor variable (X) and the outcome variable (Y). • Complete mediation exists if the predictor variable exerts its total influence via the mediating variable (M). • Partial mediation is given if the predictor variable exerts some of its influence via M, and it also exerts some of its influence directly on the outcome variable and not via M. Two mediation analyses were performed by using the guidelines of Judd and Kenny (1981), and Baron and Kenny (1986) to test whether the relationship between worry and generalized anxiety disorder, and the relationship between worry and obsessive compulsive disorder are mediated by rumination. First, we tested whether the relationship between worry and generalized anxiety disorder was mediated by rumination. The estimates of 95% CIs and summary of mediation analyses are presented in Table 3 and Figure 1. The total and direct effects of worry on generalized anxiety disorder were β = .37, p < .01, and β = .30, p < .05. The difference between the total and direct effects was the total indirect effect through the proposed mediator, with a point estimate of .075 and a 95% confidence interval of –.01105, .02740. Because zero is in the 95% confidence interval, we can conclude that rumination does not mediate the worry–GAD relationship.
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TABLE 3. Indirect Effect of Worry on Generalized Anxiety Disorder (GAD) Through Rumination (N = 60) 95% Confidence Interval
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Point estimate Z-value Std. Error Sig. (two-tailed) Sobel
0.075
1.557
0.027
0.12
Lower
Upper
−.01105 .02740
Second, we investigated whether the relationship between worry and obsessive compulsive disorder was mediated by rumination. The estimate of 95% CI and summary of mediation analyses are presented in Table 4 and Figure 2. The total and direct effects of worry on obsessive compulsive disorder were significant (β = .41, p < .01; β = .37, p
