Major depression in panic disorder patients with comorbid social phobia

171

Journal ofAffective Disorders, 22 (1991) 171-177 0 1991 Elsevier Science Publishers B.V. 01650327/91/$03.50 ADONIS 016503279100105L

JAD 00818

Major depression in panic disorder patients with comorbid social phobia Stewart

R. Reiter,

Michael

W. Otto, Mark H. Pollack and Jerrold

F. Rosenbaum

Clinical Psychopharmacology and Behavior Therapy &its, Massachusetts General Hospital and Harvard Medical School, Boston, MA, U.S.A. (Received 23 January 1991) (Revision received 21 March 1991) (Accepted 16 April 1991)

Summary Rates of depression among panic disorder patients are particularly elevated in patients with comorbid social phobia. However, it is unclear whether this association is specific to social phobia, or whether any comorbid anxiety disorder increases the risk of depression. We assessed 100 panic disorder patients and found a significantly higher incidence of lifetime major depression for panic patients with comorbid social phobia or generalized anxiety disorder (GAD). Panic patients with comorbid social phobia had significantly higher scores on measures of dysfunctional attitudes and lower scores on measures of assertiveness; these variables may mediate the link between social phobia and depression in this population.

Key words:

Panic

disorder;

Depression;

Social phobia;

Introduction A number of recent studies have focused attention on comorbid panic disorder and depression. A 63% rate of lifetime depression was reported by Stein et al. (1990a) for panic disorder patients. Similarly, Breier et al. (1986) reported that 68% of their sample of panic disorder and

Address for correspondence: Michael W. Otto, Ph.D., WACC-815, Massachusetts General Hospital, 15 Parkman St., Boston, MA 02114, U.S.A.

Dysfunctional

attitudes;

Assertiveness

agoraphobic patients met criteria for current or past episodes of major depression, and 35% of the sample had depressive episodes judged to be secondary to the agoraphobia. Lesser et al. (1988) reported similar rates (31%) for secondary depression in panic disorder and agoraphobic patients. The high rates of comorbid panic disorder and depression have been attributed to both biological and psychosocial variables, including hypotheses of a biological diathesis shared by the two disorders (Breier et al., 19841, and hypotheses that the unexpected and uncontrollable characteristics of panic attacks may cause patients to

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feel helpless and, hence, predispose to demoralization and depression (Stein et al., 1990a). Stein et al. (1989) provided data indicating that rates of depression among panic disorder patients are particularly elevated among patients with comorbid social phobia. Sixteen of 35 patients in their sample had comorbid social phobia, and 15 of the 16 (94%) reported a past history of major depression as compared to nine of 19 (47%) panic disorder patients without social phobia. The authors hypothesized that three factors may explain the increased risk of depression in panic disorder patients with comorbid social phobia: ‘psychological, particularly cognitive factors’ (p. 237) social isolation (due to social avoidance), and a greater severity of anxiety. Of these hypotheses, two were not supported by data from an expanded sample (Stein et al., 1990b); severity and duration of the panic disorder or degree of agoraphobic avoidance were not significant predictors of a lifetime history of major depression among panic disorder patients. The remaining hypothesis proposed by Stein and associates (1989) targeted psychological and cognitive factors that may predispose patients to both comorbid social phobia and depression, but these factors were not identified. It is also unclear whether any additional anxiety disorder may lead to increased rates of depression among panic disorder patients, or whether this association is specific to social phobia. Rates of depression are elevated in a number of non-panic anxiety disorders. For example, Barlow et al. (1986) found that depression was most elevated for social phobia and generalized anxiety disorder (GAD) patients, with rates of comorbid depression at 38% and 39%, respectively; 20% of obsessive compulsive disorder (OCD) patients and 9% of simple phobits had a history of depression. Mellman and Uhde (1987) also reported that comorbid OCD confers an increased risk of major depression in panic disorder patients. The present study has two goals. The first is to examine the incidence of lifetime depression in panic disorder patients with and without comorbid anxiety disorders. Although comorbid social phobia was targeted for specific examination, we also examined the association between depression in panic disorder patients and comorbid

GAD or simple phobia. The prevalence of OCD in our sample (1%) was too low for examination of rates of depression. The second goal is to identify the cognitive and behavioral factors that may account for the association between social phobia and depression. Dysfunctional attitudes and low assertiveness have each been implicated in the phenomenology and maintenance of depression, and can be measured with available instruments. The Dysfunctional Attittude Scale (DAS) was developed by Weissman (1979) to assess maladaptive cognitions which, according to Beck’s (1972) cognitive theory of depression, predispose individuals to depression. DAS scores are elevated in depressed patients, are associated with the severity and duration of the depressive episode, and often decrease significantly upon effective treatment of depression (Dohr et al., 1989; Norman et al., 1988; Peselow et al., 1990). Many of the DAS items are associated with social self-esteem and needs for approval (Parker et al., 1984; Weissman, 1979), and hence may be associated with the sensitivity to social evaluation characteristic of social phobia (Mannuzza et al., 1990). Social skills and assertiveness training may prevent relapse among hospitalized depressives, suggesting that low assertiveness is also a potential vulnerability factor for recurrent depression (Miller et al., 1989). Low assertiveness has been associated with greater levels of dysfunctional attitudes in mildly depressed subjects (Olinger et al., 1987), and is correlated with greater social anxiety (Chambless et al., 1982). These studies lend support to the hypothesis that dysfunctional attitudes and low assertiveness are common to both major depression and social phobia, and that these traits may mediate the co-occurrence of these disorders. Hence, we hypothesize that panic disorder patients with comorbid social phobia are less assertive, have more dysfunctional attitudes, and are more likely to have a history of depression than patients without comorbid social phobia. Method

Subjects and procedures Subjects for this study were the first 100 patients entered in the Massachusetts General Hos-

173

pita1 longitudinal study of panic disorder, a naturalistic study designed to provide detailed information on the course of panic disorder. Patients undergoing pharmacologic or behavioral treatment for panic disorder (with or without agoraphobia) were eligible for participation if they were between the ages of 18 and 80, provided informed consent, and were willing to keep daily diaries and undergo monthly interviews. Patients were excluded if they were psychotic within the last 3 months or had a current or past diagnosis of schizophrenia. Patients entered the study at different points including treatment onset, maintenance periods, and when discontinuing treatment. During the initial evaluation, all patients completed the self-report questionnaires and underwent a Structured Clinical Interview for DSMIIIR (Spitzer et al., 1988) to establish anxiety, affective, somatization, and substance use disorders, and to detail their history of illness and treatment. Consistent with DSM-IIIR criteria, patients received a diagnosis of comorbid social phobia only if their social fears and avoidance were unrelated to the fear of having a panic attack in such situations. One patient failed to complete the Cognitions Questionnaire and another the Rathus Assertiveness Schedule.

The second instrument was the Cognitions Questionnaire (CQ>, a 40-item questionnaire designed to provide an overall measure of depressive cognitive style as well as assess specific dimensions of negative thinking in relation to hypothetical events (Fennel1 and Campbell, 1984). One such event is the experience of depression itself, and as such a separate measure of ‘depression about depression’ is available (Fennel1 and Teasdale, 1987); in the present paper this tendency to respond to symptoms of depression with negative cognitions is termed ‘CQ-dep/dep’. Assertiveness. The Rathus Assertiveness Schedule (RAS) is a 30-item questionnaire assessing the self-report of assertiveness in a variety of common situations (Rathus, 1973). It has adequate reliability and validity, and scores can range from positive to negative 90. More positive scores reflect greater assertiveness. State depressed mood. Depressed mood was assessed with the Beck Depression Inventory (BDI; Beck et al., 1961). The BDI consists of 21 items corresponding to depressive symptoms and attitudes, discriminates depression from generalized anxiety, and is a widely used instrument for assessing depression in both clinical and nonclinical populations (Beck et al., 1988).

Measures Socioeconomic status. The Hollingshead scales are standard rating scales for assessing educational and occupational level (Hollingshead and Redlich, 1958). The scales range from 1 to 7 for education and 1 to 8 for occupation, with higher scores indicating greater education or occupational status. Dysfunctional attitudes. Two instruments were used to assess dysfunctional attitudes associated with depression. The first was the Dysfunctional Attitude Scale (DAS), a 40-item scale designed to assess attitudes thought to contribute to depression (Weissman, 1979). Scores can range from 40 to 280, with higher scores indicating greater endorsement of dysfunctional attitudes. The DAS has adequate reliability and is strongly associated with severity of depression (Dobson and Breiter, 1983).

Results

Demographics Sixty-three percent of the patients were female and 37% were male. The average age was 39.9 f 11.2 years for the females and 41.3 + 11.5 for the males. Twenty-six percent of the patients met criteria for panic disorder without current agoraphobic avoidance, and 48% with mild, 17% with and 9% with severe agoraphobic moderate, avoidance according to DSM-IIIR criteria. The average age of onset for the panic disorder was 29.8 i 11.5 years, with a duration of illness of 10.7 f 9.3 years at the time of evaluation. All patients had previous or ongoing medication trials. At the time of assessment 78% of the sample were taking benzodiazepines and 29% antidepressant medications. Seven percent of the sam-

174

ple had behavioral ation.

treatment

at the time of evalu-

Comorbid anxiety disorders and depression Fifty-seven percent of our sample of panic disorder patients met criteria for a current additional anxiety diagnosis: 30% met criteria for social phobia, 21% for GAD, 30% for simple phobia, and 1% for OCD. Of these patients, 65% met criteria for one, 26% for two, and 9% for three comorbid anxiety disorders. Fifty percent of the entire sample of panic disorder patients met criteria for a current or past major depression. The association between individual comorbid anxiety disorders and current or past major depression was examined with Pearson chi-square analyses. Comorbid OCD was not examined due to the low rate of occurrence (1%). A significant association between comorbid social phobia and major depression was obtained (x2 = 19.33, P < O.OOS), with 73.3% of the patients with social phobia also meeting criteria for a major depression compared to 40.0% of those panic patients without social phobia. Age of onset of social phobia predated that of major depression for 77% of patients with both disorders; mean age of onset was 14.1 years for social phobia and 26.7 years for major depression for this subsample. A significant association was also obtained between comorbid GAD and depression (x2 = 4.88, P < 0.05); 71.4% of patients with GAD had a history of major depression relative to only 44.3% for patients without current GAD. A significant association was not obtained between comorbid simple phobia and major depression (x2 = 0.8, NS). There was significant overlap between patients with social phobia and GAD (x2 = 12.9, P < 0.001); 13 of 30 patients with social phobia also met criteria for GAD. We examined the association of social phobia with depression independent of GAD by excluding all patients with GAD from analysis; a significant association between social phobia and major depression was maintained under these conditions (x2 = 6.1, P < 0.05). Thirteen of 21 patients with GAD also met criteria for social phobia, but the small number of remaining subjects (n = 8) did not permit evaluation of the independent relationship between GAD and depression in panic disorder patients.

Five out of these major depression.

eight patients

had a history

of

Psychological aspects of comorbid social phobia and depression A number of demographic variables were examined to assess differences between panic disorder patients with and without social phobia. These comparisons are presented in Table 1. No significant differences were found for current age, age of onset for the panic disorder, educational and occupational level, or gender. The association of dysfunctional attitudes and assertiveness with social phobia was assessed by examination of scores on the DAS, CQ (total), CQ-dep/dep, and RAS in patients with and without comorbid social phobia using MannWhitney U-tests. Patients with comorbid social phobia had significantly higher scores on each of the dysfunctional attitude measures, and lower assertiveness as indicated by the RAS. These data are presented in Table 2. As the presence of social phobia was significantly associated with a lifetime history of depression, these findings cannot be interpreted as specific to the influence of social phobia without further analysis. To control for the possible influence of current depression on these findings, additional analyses of covariante (ANCOVAs) were completed, treating baseline BDI scores as the covariate. For ANCOVA procedures to be valid, assumptions of homogeneity of regression must be met. This assump-

TABLE

1

DEMOGRAPHIC CHARACTERISTICS OF PANIC DISORDER PATIENTS WITH AND WITHOUT SOCIAL PHOBIA Social phobia

Current age Age met criteria for panic Educational level Occupation level Percent female a Significance differences tests.

Significance a

Present

Absent

40.3*11.6

40.5&11.2

NS

28.9 k 10.8 5.0_+ 1.4 5.2+ 1.5 53%

30.2+ 11.8 5.li 1.2 5.6+ 1.3 67%

NS NS NS NS

according to Mann-Whitney (percent female) were assessed

U-tests; gender with chi-square

175

tion was violated for the analysis of the CQ scores. Consequently, ANCOHET procedures appropriate for heterogeneous slopes of the covariate regression line were utilized for the CQ data. These procedures are detailed by Maxwell and Delaney (19901, and the analysis of the influence of comorbid social phobia was performed at the ‘center of accuracy’ (p. 417). For the other dependent variables - DAS, RAS, and CQdep/dep - heterogeneity of regression was not evident, and standard ANCOVA procedures were utilized. BDI scores were a significant predictor of dysfunctional attitudes as assessed by the DAS, CQ, and CQ-dep/dep (all P values < 0.001). Patients with greater current depression had more dysfunctional attitudes, and the BDI accounted for 25-42% of the variation in the dysfunctional attitude scores. BDI scores were also a significant predictor of assertiveness scores (F,,97 = 5.24, P < 0.05). With variation in BDI scores statistically controlled, the presence of comorbid social phobia continued to be a significant predictor of and dysRAS scores (F,,g, = 13.4, P < O.OOl>, functional attitudes as assessed by the DAS (F,,,, = 7.15, P < 0.05) and CQ (F,,,, = 6.23, P < 0.05). Panic disorder patients with social nhobia had lower assertiveness and greater dysfunctional attitudes. The measure of the tendency to become depressed in response to symptoms of depression (CQ-dep/dep) was not significantly elevated in social phobia patients when baseline depression was statistically controlled (F,,,, = 2.71, NS).

TABLE

Discussion Thirty percent of our cohort of panic disorder patients met criteria for social phobia. This rate was consistent with the 22% and 46% rates reported for panic disorder patients by Barlow et al. (1986) and Stein et al. (19891, respectively. Our results indicated that panic disorder patients with social phobia were no different than those without social phobia with regard to age of onset of panic disorder or pertinent demographics including education level, occupation level, and gender. Seventy-three percent of these patients met criteria for past or present major depression, compared to 40% for panic disorder patients without social phobia. These results replicate previous research finding increased rates of depression in panic disorder patients with comorbid social phobia (Stein et al., 1989). We also found that panic disorder patients with comorbid GAD, but not simple phobia, had a higher incidence of lifetime depression. Thus, comorbid anxiety disorders that are themselves associated with an increased incidence of depression (social phobia, GAD, and OCD) may result in an additive risk for depression in panic disorder patients. However, in our sample we could not assess rates of depression in panic patients with comorbid GAD independent of those with comorbid social phobia, and these findings await replication with larger and more diagnostically discrete patient samples. We hypothesized that panic disorder patients

2

MEAN VALUES AND STANDARD DEVIATIONS FOR THE DYSFUNCTIONAL ATTITUDE SCALES FOR PANIC DISORDER PATIENTS WITH AND WITHOUT SOCIAL PHOBIA Social phobia

a Significance

was evaluated

using non-parametric

139.4 f 24.4 + 4.3+ - 12.5 +

ASSERTIVENESS

Significance

Present Dysfunctional Attitude Scale Cognitions Questionnaire total Cognitions Questionnaire dep/dep Rathus Assertiveness Scale

AND

a

Absent 34.2 11.8 2.9 22.7

Mann-Whitney

116.8k25.1 17.5* 7.1 2.9k 2.1 8.4 * 23.2 U-tests

appropriate

P P P P to the unequal

< < < <

0.01 0.01 0.05 0.001

sample

sizes.

176

with comorbid social phobia would have significantly higher dysfunctional attitudes and be significantly less assertive than patients without this comorbid diagnosis. This hypothesis was supported. While controlling for level of current depression, patients with comorbid social phobia had higher dysfunctional attitudes as indicated by the Dysfunctional Attitude Scale and the Cognitions Questionnaire, and had lower assertiveness as indicated by the Rathus Assertiveness Schedule. These data are consistent with the notion that the tendency toward negative self-evaluations in social situations and low assertiveness characteristic of social phobia may predispose to depression, or may be a risk factor for both disorders. The characteristics of our sample did not allow for independent evaluation of assertiveness and dysfunctional attitudes in patients with comorbid GAD, but given the chronic worry and focus on potential harm that characterize many GAD patients, similar findings may be obtained for this disorder. In summary, the present study replicated previous findings of higher rates of depression among panic disorder patients with comorbid social phobia (Stein et al., 1989, 1990b), identified two psychological variables - dysfunctional attitudes and assertiveness - that may mediate this link with depression, and found that the association between comorbid anxiety and depression in panic disorder patients may not be specific to social phobia. Also, we cannot rule out that the presence of comorbid disorders such as social phobia or GAD may influence rates of depression as part of a general severity of illness rather than as specific predisposing factors. Nonetheless, the present study encourages the assessment of dysfunctional attitudes and assertiveness in panic disorder patients, particularly among patients with additional comorbid anxiety disorders. Once patients with highly dysfunctional attitudes or low assertiveness are identified, these patients can be targeted for additional treatment interventions such as social skills training or cognitive therapy. Acknowledgements The authors gratefully acknowledge the assistance of Gary S. Sachs, M.D., Cheryle A. O’Neal,

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