Copyright 1991 by the American Psychological Association. Inc. 0022-006X/91/S3.00
Journal of Consulting and Clinical Psychology 1991. Vol. 59, No. 2, 282-288
Cognitive Therapy With Depressed Inpatients: Specific Effects on Dysfunctional Cognitions Mark A. Whisman Pennsylvania State University
Ivan W Miller, William H. Norman, and Gabor I. Keitner
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Department of Psychiatry and Human Behavior Brown University and Butler Hospital
Specificity of cognitive change following cognitive therapy for depression was assessed in 39 depressed inpatients who completed either a standard inpatient treatment (pharmacotherapy and milieu management) or the standard treatment plus cognitive therapy. Following treatment, patients in both groups endorsed fewer dysfunctional cognitions on 2 of 4 measures of cognitive distortion. Compared with patients receiving only the standard treatment, patients also receiving cognitive therapy reported less hopelessness and fewer cognitive biases at posttreatment and 6- and 12-month follow-up assessments and fewer dysfunctional attitudes at the 6-month follow-up. Treatment effects for dysfunctional cognitions were found even though the treatment groups did not differ in depression severity, suggesting that results did not reflect state-dependent differences between treatments secondary to difference in depression.
There is a substantial body of evidence that suggests that cognitive therapy (CT) of depression, developed by Beck and his associates (Beck, 1976; Beck, Rush, Shaw, & Emery, 1979), is a highly effective treatment for nonpsychotic, unipolar depression (Dobson, 1989). Furthermore, recent evidence suggests that CT may be particularly effective at preventing relapse (e.g., Blackburn, Eunson, & Bishop, 1986; Kovacs, Rush, Beck, & Hollon, 1981; Miller, Norman, & Keitner, 1989; Simons, Murphy, Levine, & Wetzel, 1986). The treatment is based on the theoretical assumption that the characteristic set of symptoms of depression are primarily the result of the tendency to view the self, the future, and the world in a distorted, unrealistically negative manner. According to Beck, the effects of CT result from technical interventions "designed to identify, reality test, and correct distorted conceptualizations and the dysfunctional beliefs (schemes) that underlie them" (Beck et al., 1979, p. 4). Although the assumption that cognitive change results in change in the behavioral and affective symptoms of depression is central to the theoretical model proposed by Beck (but see Barber & DeRubeis, 1989; Beutler & Guest, 1989; Greenberg & Safran, 1984; Hollon, DeRubeis, & Evans, 1987, for alternative theories regarding the mechanisms of change in CT), few studies have tested its validity by looking at the specific effects of different therapies on changes in measures of cognitive distortion. As Beckham and Watkins (1989) have observed,
It is quite possible that processes held in common with other therapies (e.g., therapeutic alliance, establishment of hope) may be the central catalytic agents. A finding that cognitive therapy produces specific effects (and not just greater effects) compared to other therapies would strengthen the probability that it possesses unique and effective therapy elements, (p. 69)
The studies that have compared CT with different types of therapies on targeted measures of cognitive functioning have yielded mixed results. Simons, Garfield, and Murphy (1984) found that outpatients receiving pharmacotherapy exhibited similar changes in mood and cognitive processes and content as patients receiving CT. Moreover, they found that cognitive improvement was an important feature of overall clinical improvement, regardless of treatment modality. Studies that have compared other forms of cognitive therapy with various treatments have also failed to find differences on target-dependent measures (e.g., McLean & Hakstian, 1979; Taylor & Marshall, 1977; Zeiss, Lewinsohn, & Munoz, 1979). In contrast to these results, Rush, Beck, Kovacs, Weissenburger, and Hollon (1982) reported that CT, compared with pharmacotherapy, resulted in significantly greater improvement in hopelessness and more generalized gains in self-concept. These results, however, were confounded by the fact that CT also resulted in greater improvement in mood. Similarly, the results from a study conducted by Blackburn and Bishop (1983) found that, compared with patients receiving pharmacotherapy alone, patients receiving CT, either alone or in combination with pharmacotherapy, exhibited significant treatment effects on negative views of the self, the world, and the future. As with the results obtained by Rush et al. (1982), however, outcome on these variables mirrored outcome on measures of depression, thus arguing against a treatment-specific effect. Moreover, in both of these studies, changes on the cognitive variables were highly correlated with changes on measures of depression
This research was supported by National Institute of Mental Health Grant MH-35945, National Institutes of Health Biomedical Research Support Grant RR-05817, and a grant from the Firan Foundation. Correspondence concerning this article should be addressed to Mark A. Whisman, Department of Psychology, 417 Bruce Y Moore Building, Pennsylvania State University, University Park, Pennsylvania 16802, or to Ivan W Miller, Butler Hospital/Brown University Medical School, 345 Blackstone Boulevard, Providence, Rhode Island 02906. 282
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SPECIFIC EFFECTS ON DYSFUNCTIONAL COGNITIONS
severity. Therefore, it cannot be ruled out that the differential change observed in cognitive distortion reflected state-dependent reduction in cognition produced by greater change in depression. One problem with the aforementioned studies is the use of relatively small sample sizes and the accompanying lack of power to identify treatment effects on measures of cognitive functioning. Recently, Imber et al. (1990) presented the results of cognitive change for patients receiving CT in the National Institute of Mental Health Treatment of Depression Collaborative Research Program. The sample size of the study allowed for detection of medium-effect sizes in tests of main effects and large-effect sizes in tests of paired comparisons. At the end of treatment, patients who received CT reported lower scores on the Need for Social Approval factor on the Dysfunctional Attitude Scale (DAS; Weissman & Beck, 1978) than patients who received interpersonal psychotherapy or imipramine with supportive clinical management. Patients who received CT did not, however, differ from patients who received the other treatments on the DAS Total scale, the DAS Perfectionism factor, or Pessimism and Self-Denigration factors obtained from the Hamilton Rating Scale for Depression (Hamilton, 1967) and Beck Depression Inventory (Beck, Ward, Mendelsohn, Mock, & Erbaugh, 1961). These results, therefore, provide only limited support for specific effects of CT. The treatment effects for the DAS Need for Social Approval factor were obtained even though patients who received CT did not differ in depression severity from patients in the other treatments (Elkin et al., 1989). The results from these studies provide mixed support for the assumption that CT results in specific treatment effects on measures of cognitive contents and processes. There are, however, several limitations with the above studies. First, two of the three studies that found specific effects for CT on measures of cognitive distortion also found that CT had a greater effect on reducing depression. Consequently, the rival hypothesis, that differences between treatments observed in cognitive distortion reflect state-dependent reduction in cognition produced by greater change in depression, cannot be ruled out. Second, earlier studies have compared treatments on cognitive functioning only over the course of treatment and immediately following treatment. As such, there is a lack of research examining differences between treatments at follow-up, even though there is evidence for the greater effectiveness of CT at preventing relapse over time. Barber and DeRubeis (1989) have proposed that CT teaches a set of skills that help individuals deal with negative thoughts when they occur and that repeated use of such skills will lead to a change in the basic cognitive schemata. Accordingly, differences between treatments on measures of cognitive distortion should be greater during the follow-up period than immediately following therapy. Third, because some of the measures used in prior studies have not been standardized assessment questionnaires with established psychometric properties, it cannot be ruled out that failure to identify treatment effects may be due in part to measurement error. Similarly, prior studies have often included only measures of surface cognitive distortion (in contrast to measures of core cognitive distortion) that may be more likely to reflect state-dependent cognitive functioning. Finally, none of the studies have looked
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at the specificity of treatment effects on measures of cognitive distortion for inpatients receiving CT. Our study was conducted to test the specificity of treatmentinduced cognitive change for CT by comparing treatment changes on four measures of cognitive distortion (all of which have demonstrated psychometric properties and which cover the range of measures of surface and core cognitive functioning) for depressed inpatients receiving pharmacotherapy alone with patients receiving pharmacotherapy plus CT. Comparisons were made between the two groups before and after treatment and again at 6- and 12-month follow-up periods. At each assessment, analyses were also done on assessed depression to rule out the rival hypothesis that differences between treatments on measures of cognitive functioning reflected state dependent differences due to differences between treatments on severity of depression. It was hypothesized that patients in both treatments would endorse fewer dysfunctional cognitions following treatment. It was further predicted that patients who received CT in addition to the standard treatment would endorse fewer cognitive distortions than patients who received only the standard treatment.
Method Subjects Subjects included 55 depressed inpatients who were participating in a larger treatment outcome study (Miller, Norman, & Keitner, 1989; Miller, Norman, Keitner, Bishop, & Dow, 1989). AH patients met the following inclusion criteria: diagnosis of major depressive disorder according to their responses on the National Institute of Mental Health Diagnostic Interview Schedule (Robins, Helzer, Croughan, & Ratcliff, 1981); Beck Depression Inventory (Beck et al, 1961) score > 17; Modified Hamilton Rating Scale for Depression (Miller, Bishop, Norman, & Maddever, 1985) 17-item score > 17; and between 18 and 65 years old. Exclusionary criteria included (a) concurrent diagnosis of bipolar disorder, alcohol or drug dependence, schizophrenia, somatization disorder, antisocial personality disorder, or organic brain syndrome; (b) medical illness of a type or severity necessary to produce contraindications to tricyclic antidepressants or the possibility of producing significant depressive symptoms; and (c) recent use of medication known to result in depressive symptoms.
Treatments Thirty-one of the 55 patients were randomly assigned to either standard treatment (n = 17) or standard treatment plus CT (n = 14). All treatment began while the patient was in the hospital and continued for 20 weeks after discharge. The standard treatment included the usual hospital milieu, brief contacts with the treating psychiatrist, and antidepressant medication administered according to a semistructured medication protocol. According to the protocol, patients were to receive either amitriptyline or desipramine at a dosage of at least 150 mg/day; there was no upper limit on medication dosage. Psychiatrists were free to choose between these two antidepressants on the basis of previous treatment response, current symptoms, and clinical judgment. Other types of medications (i.e, neuroleptics, anxiolytics) could be used as clinically indicated. Once patients were stabilized, all medications were continued for the duration of the active treatment phase of the project. Approximately 75% of the patients received an optimal dosage (i.e, > 150 mg/day) of one of the antidepressants, and there were no significant differences between groups in the percentage of patients
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who received an optimal dosage. Medication management sessions occurred daily while the patient was in the hospital and five to six times during the 20-week outpatient period. CT patients received the standard treatment as outlined above and additionally received individually administered CT sessions, based on the technical and theoretical model proposed by Beck (Beck et al., 1979). These sessions occurred five times a week during the inpatient stay and weekly during the outpatient phase. In general, compliance with treatment was excellent. As discussed in greater detail in Miller, Norman, Keitner, et al. (1989), patients in both groups received approximately 19 medication and monitoring sessions during hospitalization and 7 during the outpatient phase of treatment. Patients in the CT condition received a mean of 10 psychotherapy sessions in the hospital and 18 outpatients sessions. Approximately 75% of patients received subsequent treatment following the end of the formal treatment period. There were no differences between groups in the type or amount of subsequent treatment (Miller, Norman, & Keitner, 1989). Pharmacological treatment and medication management sessions were conducted by seven board-certified psychiatrists. The CT was conducted by a PhD clinical psychologist who had 6 years experience in treating depressed patients, including being the primary therapist in a previous outcome study of CT (Blackburn, Bishop, Glen, Whalley, & Christie, 1981). Throughout the course of treatment, CT sessions were supervised to ensure treatment adherence and therapist competency. A complete description of the treatment is provided in Miller, Norman, Keitner, et al. (1989). For the present study, an additional 24 patients were added to the patients in the standard treatment condition to increase the power for between-groups analyses. These patients consisted of those who met all criteria for admission into the randomized trial but who could not be randomly assigned for one of the following reasons: (a) The patient was a pilot subject recruited to test the assessment procedures before beginning the treatment trial; (b) the patient lived too far away to return to the hospital for treatment on a weekly basis; (c) the patient's attending psychiatrist refused random assignment; or (d) the patient had a previous outpatient therapist to whom he or she wanted to return. These patients received the identical assessment sequence, but their treatment was monitored only and was not controlled in any way. They received primarily pharmacotherapy, and none of the patients received CT or intensive psychotherapy of any kind. There were no differences between the initial 17 standard treatment patients and the additional 24 patients on demographic variables, diagnoses, depression severity, measures of cognitive distortion, type or amount of treatment received, or treatment response (Miller, Norman, & Keitner, 1990). Eight patients receiving the standard treatment, 3 patients in the CT group, and 5 patients in the additional group did not complete treatment. Consequently, all analyses were conducted on those 39 patients who completed either the combined standard treatment (n = 28) or standard treatment plus CT (n = 11).
Measures Automatic Thoughts Questionnaire (ATQ; Ho/Ion & Kendall, 1980). The ATQ is a 30-item, empirically derived, self-report questionnaire that assesses the frequency with which patients experience depressotypic self-statements. Split-half reliability coefficients have been found to be approximately .97, and coefficient alphas have been found to be .96 (Hollon & Kendall; Dobson & Breiter, 1983). The ATQ has been found to exhibit a strong correlation with severity of depressive symptoms (Dobson & Breiter). Hopelessness Scale (HS; Beck, Weissman, Lester, & Trexler, 1974). The HS is a 20-item, true/false, self-report measure intended to tap the
degree of the respondent's negative expectations about the future. Beck et al. (1974) report an alpha coefficient of .93 for the HS, item-total correlation coefficients ranging from .39 to .76, and correlations with clinical ratings of hopelessness of .62-86. Cognitive Bias Questionnaire (CBQ; Krantz & Hammen, 1979; Norman, Miller, & Klee, 1983). The version of the CBQ used in our study consisted of four problematic situations adapted for clinical patients, which were followed by multiple-choice questions pertaining to the protagonists' thoughts and feelings. Each response was coded according to two dichotomous and crossed dimensions: (a) depressed versus nondepressed in tone and mood and (b) distorted versus nondistorted in terms of logical inference. The response category used in the current study was the depressed-distorted option, which contains examples of Beck's typology of logical errors. The CBQ has been shown to have alpha coefficients of .62 and .69 and test-retest correlations of .48 and .60 over 4-8 weeks (Krantz and Hammen). Dysfunctional Attitude Scale (DAS; Weissman & Beck, 1978). The DAS is a 40-item, self-report questionnaire in which respondents indicate the extent of their agreement with a series of attitudinal statements on a 7-point scale. These attitudes are hypothesized by Beck's theory to be underlying risk factors toward depression. The DAS has been shown to have high internal consistency (a = .90) and reasonable stability (r = .73 over 6 weeks; Oliver & Baumgart, 1985; Dobson & Breiter, 1983). Modified Hamilton Rating Scale for Depression (MHRSD; Miller et al, 1985). The MHRSD is a 25-item modification of the Hamilton Rating Scale for Depression (HRSD; Hamilton, 1967), which was modified to include a greater sample of depressive symptoms, increase the specificity and linearity of rating points, and include standard prompt questions so that the scale could be administered by paraprofessional raters. The MHRSD has a 25-item score that reflects a total of all symptoms and a 17-item score that is equivalent to the original HRSD. For the current study, the 17-item score was used to make the results comparable with other studies using the HRSD. Reliability and validity data on the MHRSD have been presented elsewhere (Miller et al., 1985). Patients completed the above assessment instruments before initiation of treatment, at the end of treatment (20 weeks postdischarge), and at the 6- and 12-month follow-up periods.
Results Data Analyses Within-group changes on measures of cognitive distortion from pretreatment to posttreatment were analyzed using paired / tests of correlated means. The alpha level was corrected for the number of instruments, such that the significance level was set to .0125 (i.e., .05/4). At each of the four assessment periods, between-groups comparisons on measures of cognitive distortion were analyzed using multivariate analysis of variance (MANOVA). If the results of the MANOVA were significant, one-way analysis of variance (ANOVA) was conducted on each of the four measures of cognitive functioning. One-way ANOVAs were also conducted on the MHRSD to compare the two treatments on depression severity at each assessment period. Analyses were done on those patients who completed treatment (n = 39), and endpoint analyses with replacement scores were used during follow-up (i.e., to keep the n constant at each analysis, scores from the last assessment were used if patients failed to return their follow-up questionnaires).
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SPECIFIC EFFECTS ON DYSFUNCTIONAL COGNITIONS
Pretreatment
8.61, SD = 7.25) and patients who additionally received CT (M = 8.00, SD= 7.18). The M ANOVA comparing the two treatments on measures of cognitive distortion, however, was significant, .F(4,34) = 2.62, p < .05. As can be seen in Table 2, patients who received CT reported less hopelessness, F(l, 37) = 4.91; fewer dysfunctional attitudes, F(l, 37) = 5.31; and fewer cognitive biases, F(l, 37) = 5.41, all ps < .05, than did patients who did not receive CT.
Chi-square analyses and one-way ANOVAs failed to find any differences between patients receiving standard treatment and those additionally receiving CT on demographics, depression severity, or diagnoses. These descriptive characteristics of the sample are provided in Table 1. At pretreatment, the M ANOVA for the four cognitive variables was not statistically significant, F(4, 34) = 2.18, ns, suggesting that the two treatment groups were comparable on measures of cognitive distortion at pretreatment.
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Posttreatment The results from the paired / tests indicate that patients receiving only the standard treatment exhibited significant pretreatment to posttreatment decreases in cognitive distortion as measured by the ATQ, r(27) = 6.03, p < .001, and the HS, t(21) = 3.82, p < .001, but not by the DAS, /(27) = 2.26, ns, or the CBQ, r(27) = .78, ns. Similarly, patients receiving CT in addition to the standard treatment reported significant pretreatment to posttreatment decreases on the ATQ, r(10) = 6.03, p < .001, and the HS, ;(10) = 4.08, p < .005, but no significant change on the DAS, J(10) = 2.48, ns, or the CBQ, f(10) = 1.90, ns. At posttreatment, there was no significant difference, F(l, 37) = .33, ns, in depression severity as measured by the MHRSD between patients in the standard treatment (M = 8.11, SD = 6.72) and patients who additionally received CT (M= 6.64, SD = 8.47). The M ANOVA comparing patients in the two treatment conditions on the measures of cognitive distortion, however, was statistically significant, F(4, 34) = 4.61, p < .005. The results from the one-way ANOVAs indicate that patients who additionally received CT reported less hopelessness, F(l, 37) = 13.38, p < .001, and fewer cognitive biases, ^(1, 37) = 5.12, p < .05, than did patients in the standard treatment (Table 2). Six-Month Follow-Up At the 6-month follow-up, there was no significant difference, F(l, 37) = .06, ns, in depression severity as measured by the MHRSD between patients in the standard treatment (M =
Twelve-Month Follow-Up At the 12-month follow-up, there was no significant difference, F(i, 37) = .02, ns, in severity of depression as measured by the MHRSD between patients in the standard treatment (M = 6.79, SD = 7.19) and patients who received CT in addition to the standard treatment (M= 6.46, SD = 7.44). The MANOVA testing for differences between the two treatments on measures of cognitive distortion, however, was significant, F(4, 34) = 2.96, p < .05. As can be seen in Table 2, one year following therapy, patients who received the additional CT continued to report less hopelessness, F(\, 37) = 6.41, and fewer cognitive biases, F(l, 37) = 6.67, both ps < .05, than did patients who received only the standard treatment. Discussion Our study was conducted to test the specificity of treatmentinduced cognitive change for CT by comparing treatment changes on four measures of cognitive distortion for depressed inpatients receiving pharmacotherapy alone with patients receiving pharmacotherapy plus CT. We expanded on previous research in this area by using standardized assessment questionnaires that measure surface and core cognitive distortions and by making comparisons between the two treatment conditions during the follow-up period (in addition to posttreatment comparisons). We hypothesized that patients in both treatments would endorse fewer dysfunctional cognitions following therapy. We also predicted that patients who received CT in addition to the standard treatment would endorse fewer dysfunctional cognitions than patients who received only the standard treatment.
Table 1 Demographic and Depression Characteristics for Depressed Inpatient Sample Characteristic Age (in years) Female Attended college Married Modified Hamilton Rating Scale for Depression Beck Depression Inventory Age of onset (in years) Recurrent depression No. of previous episodes Dysthymia diagnosis Melancholia diagnosis Psychotic depression diagnosis
M
SD
34.69
10.95
22.44 27.08 25.03
3.95 7.75 11.29
7.35
8.95
84.60 48.70 71.80
86.80 49.09 27.27 9.09
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Table 2 Means and Standard Deviations on Cognitive Distortion Measures Pretreatment
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Measure Automatic Thoughts Questionnaire Standard Tx Cognitive Tx Hopelessness Scale Standard Tx Cognitive Tx Cognitive Bias Questionnaire Standard Tx Cognitive Tx Dysfunctional Attitude Scale Standard Tx Cognitive Tx
Posttreatment
6 months
12 months
SD
M
SD
M
SD
61.89 45.36
33.78 28.73
62.04 47.64
33.68 33.58
58.04 42.64
32.44 16.94
5.12 5.02
8.71 1.36
6.59 0.92
7.75 3.00
6.51 4.47
7.54 2.27
6.68 2.45
3.00 1.36
3.12 1.36
2.71 0.64
2.93 1.21
2.96 0.82
2.98 0.98
1.93 0.27
2.07 0.65
151.93 143.27
44.18 37.35
138.82 114.73
50.92 22.72
138.36 102.18
46.48 36.96
137.57 109.91
48.69 41.12
M
SD
100.93 97.09
25.49 27.10
12.43 7.82
Note. Tx = treatment.
The first hypothesis was generally confirmed. Compared with their pretreatment scores, patients in both treatments reported significantly less hopelessness and fewer automatic thoughts at the end of treatment. These findings are consistent with earlier studies (e.g., Blackburn & Bishop, 1983; Rush et al, 1982; Simons et al., 1984). Hollon et al. (1987) have proposed a number of causal mediational models of cognitive change within comparative treatment studies that may account for these findings. The models differ in the role that is placed on causal specificity/nonspecificity and consequential specificity/ nonspecificity. These authors propose that cognitive change is a causal mediator of change in depression forCT but not pharmacotherapy (causal specificity) and that change in depression for both treatment conditions produces consequent changes in cognitions (consequential nonspecificity). Future research using structural or causal modeling strategies is necessary to evaluate this proposed mediational model of change. Although the two treatments evidenced significant change on the measures of hopelessness and automatic thoughts, there were no significant pretreatment to posttreatment changes on measures of dysfunctional attitudes or cognitive biases for either treatment. This may be explained by the nature of the measures. The HS and ATQ are often conceptualized as measures of surface cognition, whereas the DAS and CBQ are conceptualized as measures of core cognitive functioning. As such, it would be expected that the treatments would have a greater impact on reducing surface cognitive distortion than core cognitive distortion. The lack of significant pretreatment to posttreatment change on the DAS and CBQ may also be explained in part by the small sample size and the accompanying lack of power to identify changes in these measures following treatment. The second hypothesis was also generally confirmed. Compared with patients who received only the standard treatment, patients who additionally received CT reported less hopelessness and fewer cognitive biases at posttreatment and at 6-month and 12-month follow-up assessments and fewer dysfunctional
attitudes at the 6-month follow-up. These differences between treatments were significant even though the two treatments did not differ in concurrent depression severity. These findings argue against the rival hypothesis that, compared with patients who received the standard treatment only, patients who received the additional CT would report less cognitive distortion due to greater state-dependent reduction in cognitive distortion produced by greater change in depression. To further rule out this alternative hypothesis, the significant univariate tests were reanalyzed, while statistically controlling for concurrent depression. The results of these analyses of covariance were consistent with the results of the ANOVAs. When level of depression was statistically controlled for, the addition of CT to the standard treatment resulted in less hopelessness and fewer cognitive biases at posttreatment and at the 6- and 12-month followups and fewer dysfunctional attitudes at the 6-month follow-up. There was, however, significant (p < .05) heterogeneity of regression for the posttreatment and 12-month follow-up assessments on the HS, so these specific results should be interpreted with caution. The central finding that CT, in comparison with standard pharmacotherapy, produces specific effects on measures of cognitive distortion strengthens the probability that CT possesses unique and effective therapy elements (Beckham & Watkins, 1989). In addition to differences on measures of cognitive distortion observed between treatments at posttreatment, our study is the first to document that these differences were maintained at follow-up. According to cognitive theory of depression, individuals who endorse fewer cognitive distortions are less likely to become depressed when they encounter negative events in their lives. Consequently, the current finding that patients who additionally received CT endorsed fewer cognitive distortions at posttreatment and follow-up than patients who received only the standard treatment may help to explain why CT has recently been shown to result in lower relapse rates during follow-up. Significant differences between treatment conditions were
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SPECIFIC EFFECTS ON DYSFUNCTIONAL COGNITIONS found on all measures except the ATQ. Results from past studies using the ATQ have suggested that it correlates highly with depressive severity and may be considered a state-dependent measure (e.g., Dobson & Shaw, 1986; Dohr, Rush, & Bernstein, 1989). As such, it may be expected to be less sensitive to between-groups treatment differences in cognitive distortion that are independent of depression severity. In the current study, we compared the impact of adding a CT component to a standard pharmacological inpatient treatment. We were unable, however, to test for differences between CT alone and the standard treatment on measures of cognitive distortion over time, and future research is needed to examine these comparisons. Similarly, the results were obtained with depressed inpatients, and further research is needed to determine whether the results can be generalized to depressed outpatients. Finally, the current study was conducted before the development of competency rating scales for CT. Although the CT sessions were closely supervised, and although the therapist was an experienced CT therapist and the outcome was similar to other clinical trials of CT (Miller, Norman, & Keitner, 1989; Miller, Norman, Keitner, et al., 1989), the current results cannot be generalized to all CT therapists who meet acceptable criteria for CT competency until the results are replicated with such a group of therapists. The obtained results do, however, suggest that future research examining specificity of cognitive change within CT should include a comprehensive assessment of cognitive distortion (including psychometrically established measures of surface and core dysfunctional cognitions) assessed during follow-up, in addition to posttreatment comparisons.
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treatment trial using cognitive therapy and pharmacotherapy, each alone and in combination. British Journal of Psychiatry, 139, 181189. Blackburn, I. M., Eunson, K. M., & Bishop, S. (1986). A two-year naturalistic follow-up of depressed patients treated with cognitive therapy, pharmacotherapy and a combination of both. Journal of Affective Disorders, 10, 67-75. Dobson, K. S. (1989). A meta-analysis of the efficacy of cognitive therapy for depression. Journal of Consulting and Clinical Psychology, 57, 414-419. Dobson, K. S., & Breiter, H. J. (1983). Cognitive assessment of depression: Reliability and validity of three measures. Journal of Abnormal Psychology, 92,107-109. Dobson, K. S., & Shaw, B. F. (1986). Cognitive assessment with major depressive disorders. Cognitive Therapy and Research, 10,13-29. Dohr, K. B., Rush, A. J., & Bernstein, I. H. (1989). Cognitive biases and depression. Journal of Abnormal Psychology, 98, 263-267. Elkin, I., Shea, T., Watkins, J. X, Imber, S. D, Sotsky, S. M., Collins, J. F, Glass, D. R., Pilkonis, P. A., Leber, W R., Docherty, J. P., Fiester, S. J., & Paroloff, M. B. (1989). National Institute of Mental Health Treatment of Depression Collaborative Research Program: General effectiveness of treatments. Archives of General Psychiatry, 46, 971-982. Greenberg, L. S., & Safran, J. D. (1984). Integrating affect and cognition: A perspective on the process of therapeutic change. Cognitive Therapy and Research, 8, 559-578. Hamilton, M. A. (1967). Development of a rating scale for primary depressive illness. British Journal of Social and Clinical Psychology, 6, 278-296. Hollon, S. D., DeRubeis, R. J., & Evans, M. D. (1987). Causal mediation of change in treatment for depression: Discriminating between nonspecificity and noncausality. Psychological Bulletin, 102, 139-149. Hollon, S., & Kendall, P. (1980). Cognitive self-statements in depression: Development of an automatic thoughts questionnaire. Cognitive Therapy and Research, 4, 383-396. Imber, S. D, Pilkonis, P. A., Sotsky, S. M., Elkin, I., Watkins, J. X, Collins, J. F, Shea, M. X, Leber, W R., & Glass, D. R. (1990). Modespecific effects among three treatments for depression. Journal of Consulting and Clinical Psychology, 58, 352-359. Kovacs, M., Rush, A. J., Beck, A. X, & Hollon, S. D. (1981). Depressed outpatients treated with cognitive therapy or pharmacotherapy: A one-year follow-up. Archives of General Psychiatry, 38, 33-39. Krantz, S. E., & Hammen, C. L. (1979). Assessment of cognitive bias in depression. Journal of Abnormal Psychology, 88, 611-619. McLean, P., & Hakstian, A. R. (1979). Clinical depression: Comparative efficacy of outpatient treatment. Journal of Consulting and Clinical Psychology, 47, 815-836. Miller, I. W, Bishop, S., Norman, W H., & Maddever, H. (1985). Xhe Modified Hamilton Rating Scale for Depression: Reliability and validity. Psychiatry Research, 14,131-142. Miller, I. W, Norman, W H., & Keitner, G. I. (1989). Cognitive-behavioral treatment of depressed inpatients: Six- and twelve-month follow-up. American Journal of Psychiatry, 146, 1274-1279. Miller, I. W, Norman, W H., & Keitner, G. I. (1990). Treatment response of high cognitive dysfunction depressed inpatients. Comprehensive Psychiatry, 30, 62-71. Miller, I. W, Norman, W H., Keitner, G. I., Bishop, S. B., & Dow, M. G. (1989). Cognitive-behavioral treatment of depressed inpatients. Behavior Therapy, 20, 25-47. Norman, W, Miller, I., & Klee, S. (1983). Assessment of cognitive distortion in a clinically depressed population. Cognitive Therapy and Research, 7, 133-140. Oliver, J. M., & Baumgart, E. P. (1985). The Dysfunctional Attitude
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Scale: Psychometric properties and relation to depression in an unselected adult population. Cognitive Therapy and Research, 9, 161167. Robins, L. N., Helzer, J. E., Croughan, J., & Ratcliff, K. S. (1981). The NIMH Diagnostic Interview Schedule: Its history, characteristics, and validity. Archives of General Psychiatry, 38, 381-389. Rush, A. J., Beck, A. T., Kovacs, M., Weissenburger, J., & Hollon, S. D. (1982). Comparison of the effects of cognitive therapy and pharmacotherapy on hopelessness and self-concept. American Journal of Psychiatry, 139, 862-866. Simons, A. D., Garfield, S. L., & Murphy, G. E. (1984). The process of change in cognitive therapy and pharmacotherapy for depression. Archives of General Psychiatry, 41, 45-51. Simons, A. D, Murphy, G. E., Levine, J. L., & Wetzel, R. D. (1986). Cognitive therapy and pharmacotherapy for depression: Sustained improvement over one year. Archives of General Psychiatry, 43, 43-48.
Taylor, F. G, & Marshall, W L. (1977). Experimental analyses of a cognitive behavioral therapy for depression. Cognitive Therapy and Research, 1, 59-72. Weissman, A. N., & Beck, A. T. (1978, March). Development and validation of the Dysfunctional Attitude Scale: A preliminary investigation. Paper presented at the meeting of the American Educational Research Association, Toronto, Ontario, Canada. Zeiss, A. M., Lewinsohn, P. M., & Munoz, R. F. (1979). Nonspecific improvement effects in depression using interpersonal cognitive and pleasant events focused treatment. Journal of Consulting and Clinical Psychology, 47, 427-439.
Received March 26,1990 Revision received August 30,1990 Accepted August 31,1990 •
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Journal of Consulting and Clinical Psychology 1991. Vol. 59, No. 2, 282-288
Cognitive Therapy With Depressed Inpatients: Specific Effects on Dysfunctional Cognitions Mark A. Whisman Pennsylvania State University
Ivan W Miller, William H. Norman, and Gabor I. Keitner
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Department of Psychiatry and Human Behavior Brown University and Butler Hospital
Specificity of cognitive change following cognitive therapy for depression was assessed in 39 depressed inpatients who completed either a standard inpatient treatment (pharmacotherapy and milieu management) or the standard treatment plus cognitive therapy. Following treatment, patients in both groups endorsed fewer dysfunctional cognitions on 2 of 4 measures of cognitive distortion. Compared with patients receiving only the standard treatment, patients also receiving cognitive therapy reported less hopelessness and fewer cognitive biases at posttreatment and 6- and 12-month follow-up assessments and fewer dysfunctional attitudes at the 6-month follow-up. Treatment effects for dysfunctional cognitions were found even though the treatment groups did not differ in depression severity, suggesting that results did not reflect state-dependent differences between treatments secondary to difference in depression.
There is a substantial body of evidence that suggests that cognitive therapy (CT) of depression, developed by Beck and his associates (Beck, 1976; Beck, Rush, Shaw, & Emery, 1979), is a highly effective treatment for nonpsychotic, unipolar depression (Dobson, 1989). Furthermore, recent evidence suggests that CT may be particularly effective at preventing relapse (e.g., Blackburn, Eunson, & Bishop, 1986; Kovacs, Rush, Beck, & Hollon, 1981; Miller, Norman, & Keitner, 1989; Simons, Murphy, Levine, & Wetzel, 1986). The treatment is based on the theoretical assumption that the characteristic set of symptoms of depression are primarily the result of the tendency to view the self, the future, and the world in a distorted, unrealistically negative manner. According to Beck, the effects of CT result from technical interventions "designed to identify, reality test, and correct distorted conceptualizations and the dysfunctional beliefs (schemes) that underlie them" (Beck et al., 1979, p. 4). Although the assumption that cognitive change results in change in the behavioral and affective symptoms of depression is central to the theoretical model proposed by Beck (but see Barber & DeRubeis, 1989; Beutler & Guest, 1989; Greenberg & Safran, 1984; Hollon, DeRubeis, & Evans, 1987, for alternative theories regarding the mechanisms of change in CT), few studies have tested its validity by looking at the specific effects of different therapies on changes in measures of cognitive distortion. As Beckham and Watkins (1989) have observed,
It is quite possible that processes held in common with other therapies (e.g., therapeutic alliance, establishment of hope) may be the central catalytic agents. A finding that cognitive therapy produces specific effects (and not just greater effects) compared to other therapies would strengthen the probability that it possesses unique and effective therapy elements, (p. 69)
The studies that have compared CT with different types of therapies on targeted measures of cognitive functioning have yielded mixed results. Simons, Garfield, and Murphy (1984) found that outpatients receiving pharmacotherapy exhibited similar changes in mood and cognitive processes and content as patients receiving CT. Moreover, they found that cognitive improvement was an important feature of overall clinical improvement, regardless of treatment modality. Studies that have compared other forms of cognitive therapy with various treatments have also failed to find differences on target-dependent measures (e.g., McLean & Hakstian, 1979; Taylor & Marshall, 1977; Zeiss, Lewinsohn, & Munoz, 1979). In contrast to these results, Rush, Beck, Kovacs, Weissenburger, and Hollon (1982) reported that CT, compared with pharmacotherapy, resulted in significantly greater improvement in hopelessness and more generalized gains in self-concept. These results, however, were confounded by the fact that CT also resulted in greater improvement in mood. Similarly, the results from a study conducted by Blackburn and Bishop (1983) found that, compared with patients receiving pharmacotherapy alone, patients receiving CT, either alone or in combination with pharmacotherapy, exhibited significant treatment effects on negative views of the self, the world, and the future. As with the results obtained by Rush et al. (1982), however, outcome on these variables mirrored outcome on measures of depression, thus arguing against a treatment-specific effect. Moreover, in both of these studies, changes on the cognitive variables were highly correlated with changes on measures of depression
This research was supported by National Institute of Mental Health Grant MH-35945, National Institutes of Health Biomedical Research Support Grant RR-05817, and a grant from the Firan Foundation. Correspondence concerning this article should be addressed to Mark A. Whisman, Department of Psychology, 417 Bruce Y Moore Building, Pennsylvania State University, University Park, Pennsylvania 16802, or to Ivan W Miller, Butler Hospital/Brown University Medical School, 345 Blackstone Boulevard, Providence, Rhode Island 02906. 282
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SPECIFIC EFFECTS ON DYSFUNCTIONAL COGNITIONS
severity. Therefore, it cannot be ruled out that the differential change observed in cognitive distortion reflected state-dependent reduction in cognition produced by greater change in depression. One problem with the aforementioned studies is the use of relatively small sample sizes and the accompanying lack of power to identify treatment effects on measures of cognitive functioning. Recently, Imber et al. (1990) presented the results of cognitive change for patients receiving CT in the National Institute of Mental Health Treatment of Depression Collaborative Research Program. The sample size of the study allowed for detection of medium-effect sizes in tests of main effects and large-effect sizes in tests of paired comparisons. At the end of treatment, patients who received CT reported lower scores on the Need for Social Approval factor on the Dysfunctional Attitude Scale (DAS; Weissman & Beck, 1978) than patients who received interpersonal psychotherapy or imipramine with supportive clinical management. Patients who received CT did not, however, differ from patients who received the other treatments on the DAS Total scale, the DAS Perfectionism factor, or Pessimism and Self-Denigration factors obtained from the Hamilton Rating Scale for Depression (Hamilton, 1967) and Beck Depression Inventory (Beck, Ward, Mendelsohn, Mock, & Erbaugh, 1961). These results, therefore, provide only limited support for specific effects of CT. The treatment effects for the DAS Need for Social Approval factor were obtained even though patients who received CT did not differ in depression severity from patients in the other treatments (Elkin et al., 1989). The results from these studies provide mixed support for the assumption that CT results in specific treatment effects on measures of cognitive contents and processes. There are, however, several limitations with the above studies. First, two of the three studies that found specific effects for CT on measures of cognitive distortion also found that CT had a greater effect on reducing depression. Consequently, the rival hypothesis, that differences between treatments observed in cognitive distortion reflect state-dependent reduction in cognition produced by greater change in depression, cannot be ruled out. Second, earlier studies have compared treatments on cognitive functioning only over the course of treatment and immediately following treatment. As such, there is a lack of research examining differences between treatments at follow-up, even though there is evidence for the greater effectiveness of CT at preventing relapse over time. Barber and DeRubeis (1989) have proposed that CT teaches a set of skills that help individuals deal with negative thoughts when they occur and that repeated use of such skills will lead to a change in the basic cognitive schemata. Accordingly, differences between treatments on measures of cognitive distortion should be greater during the follow-up period than immediately following therapy. Third, because some of the measures used in prior studies have not been standardized assessment questionnaires with established psychometric properties, it cannot be ruled out that failure to identify treatment effects may be due in part to measurement error. Similarly, prior studies have often included only measures of surface cognitive distortion (in contrast to measures of core cognitive distortion) that may be more likely to reflect state-dependent cognitive functioning. Finally, none of the studies have looked
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at the specificity of treatment effects on measures of cognitive distortion for inpatients receiving CT. Our study was conducted to test the specificity of treatmentinduced cognitive change for CT by comparing treatment changes on four measures of cognitive distortion (all of which have demonstrated psychometric properties and which cover the range of measures of surface and core cognitive functioning) for depressed inpatients receiving pharmacotherapy alone with patients receiving pharmacotherapy plus CT. Comparisons were made between the two groups before and after treatment and again at 6- and 12-month follow-up periods. At each assessment, analyses were also done on assessed depression to rule out the rival hypothesis that differences between treatments on measures of cognitive functioning reflected state dependent differences due to differences between treatments on severity of depression. It was hypothesized that patients in both treatments would endorse fewer dysfunctional cognitions following treatment. It was further predicted that patients who received CT in addition to the standard treatment would endorse fewer cognitive distortions than patients who received only the standard treatment.
Method Subjects Subjects included 55 depressed inpatients who were participating in a larger treatment outcome study (Miller, Norman, & Keitner, 1989; Miller, Norman, Keitner, Bishop, & Dow, 1989). AH patients met the following inclusion criteria: diagnosis of major depressive disorder according to their responses on the National Institute of Mental Health Diagnostic Interview Schedule (Robins, Helzer, Croughan, & Ratcliff, 1981); Beck Depression Inventory (Beck et al, 1961) score > 17; Modified Hamilton Rating Scale for Depression (Miller, Bishop, Norman, & Maddever, 1985) 17-item score > 17; and between 18 and 65 years old. Exclusionary criteria included (a) concurrent diagnosis of bipolar disorder, alcohol or drug dependence, schizophrenia, somatization disorder, antisocial personality disorder, or organic brain syndrome; (b) medical illness of a type or severity necessary to produce contraindications to tricyclic antidepressants or the possibility of producing significant depressive symptoms; and (c) recent use of medication known to result in depressive symptoms.
Treatments Thirty-one of the 55 patients were randomly assigned to either standard treatment (n = 17) or standard treatment plus CT (n = 14). All treatment began while the patient was in the hospital and continued for 20 weeks after discharge. The standard treatment included the usual hospital milieu, brief contacts with the treating psychiatrist, and antidepressant medication administered according to a semistructured medication protocol. According to the protocol, patients were to receive either amitriptyline or desipramine at a dosage of at least 150 mg/day; there was no upper limit on medication dosage. Psychiatrists were free to choose between these two antidepressants on the basis of previous treatment response, current symptoms, and clinical judgment. Other types of medications (i.e, neuroleptics, anxiolytics) could be used as clinically indicated. Once patients were stabilized, all medications were continued for the duration of the active treatment phase of the project. Approximately 75% of the patients received an optimal dosage (i.e, > 150 mg/day) of one of the antidepressants, and there were no significant differences between groups in the percentage of patients
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who received an optimal dosage. Medication management sessions occurred daily while the patient was in the hospital and five to six times during the 20-week outpatient period. CT patients received the standard treatment as outlined above and additionally received individually administered CT sessions, based on the technical and theoretical model proposed by Beck (Beck et al., 1979). These sessions occurred five times a week during the inpatient stay and weekly during the outpatient phase. In general, compliance with treatment was excellent. As discussed in greater detail in Miller, Norman, Keitner, et al. (1989), patients in both groups received approximately 19 medication and monitoring sessions during hospitalization and 7 during the outpatient phase of treatment. Patients in the CT condition received a mean of 10 psychotherapy sessions in the hospital and 18 outpatients sessions. Approximately 75% of patients received subsequent treatment following the end of the formal treatment period. There were no differences between groups in the type or amount of subsequent treatment (Miller, Norman, & Keitner, 1989). Pharmacological treatment and medication management sessions were conducted by seven board-certified psychiatrists. The CT was conducted by a PhD clinical psychologist who had 6 years experience in treating depressed patients, including being the primary therapist in a previous outcome study of CT (Blackburn, Bishop, Glen, Whalley, & Christie, 1981). Throughout the course of treatment, CT sessions were supervised to ensure treatment adherence and therapist competency. A complete description of the treatment is provided in Miller, Norman, Keitner, et al. (1989). For the present study, an additional 24 patients were added to the patients in the standard treatment condition to increase the power for between-groups analyses. These patients consisted of those who met all criteria for admission into the randomized trial but who could not be randomly assigned for one of the following reasons: (a) The patient was a pilot subject recruited to test the assessment procedures before beginning the treatment trial; (b) the patient lived too far away to return to the hospital for treatment on a weekly basis; (c) the patient's attending psychiatrist refused random assignment; or (d) the patient had a previous outpatient therapist to whom he or she wanted to return. These patients received the identical assessment sequence, but their treatment was monitored only and was not controlled in any way. They received primarily pharmacotherapy, and none of the patients received CT or intensive psychotherapy of any kind. There were no differences between the initial 17 standard treatment patients and the additional 24 patients on demographic variables, diagnoses, depression severity, measures of cognitive distortion, type or amount of treatment received, or treatment response (Miller, Norman, & Keitner, 1990). Eight patients receiving the standard treatment, 3 patients in the CT group, and 5 patients in the additional group did not complete treatment. Consequently, all analyses were conducted on those 39 patients who completed either the combined standard treatment (n = 28) or standard treatment plus CT (n = 11).
Measures Automatic Thoughts Questionnaire (ATQ; Ho/Ion & Kendall, 1980). The ATQ is a 30-item, empirically derived, self-report questionnaire that assesses the frequency with which patients experience depressotypic self-statements. Split-half reliability coefficients have been found to be approximately .97, and coefficient alphas have been found to be .96 (Hollon & Kendall; Dobson & Breiter, 1983). The ATQ has been found to exhibit a strong correlation with severity of depressive symptoms (Dobson & Breiter). Hopelessness Scale (HS; Beck, Weissman, Lester, & Trexler, 1974). The HS is a 20-item, true/false, self-report measure intended to tap the
degree of the respondent's negative expectations about the future. Beck et al. (1974) report an alpha coefficient of .93 for the HS, item-total correlation coefficients ranging from .39 to .76, and correlations with clinical ratings of hopelessness of .62-86. Cognitive Bias Questionnaire (CBQ; Krantz & Hammen, 1979; Norman, Miller, & Klee, 1983). The version of the CBQ used in our study consisted of four problematic situations adapted for clinical patients, which were followed by multiple-choice questions pertaining to the protagonists' thoughts and feelings. Each response was coded according to two dichotomous and crossed dimensions: (a) depressed versus nondepressed in tone and mood and (b) distorted versus nondistorted in terms of logical inference. The response category used in the current study was the depressed-distorted option, which contains examples of Beck's typology of logical errors. The CBQ has been shown to have alpha coefficients of .62 and .69 and test-retest correlations of .48 and .60 over 4-8 weeks (Krantz and Hammen). Dysfunctional Attitude Scale (DAS; Weissman & Beck, 1978). The DAS is a 40-item, self-report questionnaire in which respondents indicate the extent of their agreement with a series of attitudinal statements on a 7-point scale. These attitudes are hypothesized by Beck's theory to be underlying risk factors toward depression. The DAS has been shown to have high internal consistency (a = .90) and reasonable stability (r = .73 over 6 weeks; Oliver & Baumgart, 1985; Dobson & Breiter, 1983). Modified Hamilton Rating Scale for Depression (MHRSD; Miller et al, 1985). The MHRSD is a 25-item modification of the Hamilton Rating Scale for Depression (HRSD; Hamilton, 1967), which was modified to include a greater sample of depressive symptoms, increase the specificity and linearity of rating points, and include standard prompt questions so that the scale could be administered by paraprofessional raters. The MHRSD has a 25-item score that reflects a total of all symptoms and a 17-item score that is equivalent to the original HRSD. For the current study, the 17-item score was used to make the results comparable with other studies using the HRSD. Reliability and validity data on the MHRSD have been presented elsewhere (Miller et al., 1985). Patients completed the above assessment instruments before initiation of treatment, at the end of treatment (20 weeks postdischarge), and at the 6- and 12-month follow-up periods.
Results Data Analyses Within-group changes on measures of cognitive distortion from pretreatment to posttreatment were analyzed using paired / tests of correlated means. The alpha level was corrected for the number of instruments, such that the significance level was set to .0125 (i.e., .05/4). At each of the four assessment periods, between-groups comparisons on measures of cognitive distortion were analyzed using multivariate analysis of variance (MANOVA). If the results of the MANOVA were significant, one-way analysis of variance (ANOVA) was conducted on each of the four measures of cognitive functioning. One-way ANOVAs were also conducted on the MHRSD to compare the two treatments on depression severity at each assessment period. Analyses were done on those patients who completed treatment (n = 39), and endpoint analyses with replacement scores were used during follow-up (i.e., to keep the n constant at each analysis, scores from the last assessment were used if patients failed to return their follow-up questionnaires).
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SPECIFIC EFFECTS ON DYSFUNCTIONAL COGNITIONS
Pretreatment
8.61, SD = 7.25) and patients who additionally received CT (M = 8.00, SD= 7.18). The M ANOVA comparing the two treatments on measures of cognitive distortion, however, was significant, .F(4,34) = 2.62, p < .05. As can be seen in Table 2, patients who received CT reported less hopelessness, F(l, 37) = 4.91; fewer dysfunctional attitudes, F(l, 37) = 5.31; and fewer cognitive biases, F(l, 37) = 5.41, all ps < .05, than did patients who did not receive CT.
Chi-square analyses and one-way ANOVAs failed to find any differences between patients receiving standard treatment and those additionally receiving CT on demographics, depression severity, or diagnoses. These descriptive characteristics of the sample are provided in Table 1. At pretreatment, the M ANOVA for the four cognitive variables was not statistically significant, F(4, 34) = 2.18, ns, suggesting that the two treatment groups were comparable on measures of cognitive distortion at pretreatment.
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Posttreatment The results from the paired / tests indicate that patients receiving only the standard treatment exhibited significant pretreatment to posttreatment decreases in cognitive distortion as measured by the ATQ, r(27) = 6.03, p < .001, and the HS, t(21) = 3.82, p < .001, but not by the DAS, /(27) = 2.26, ns, or the CBQ, r(27) = .78, ns. Similarly, patients receiving CT in addition to the standard treatment reported significant pretreatment to posttreatment decreases on the ATQ, r(10) = 6.03, p < .001, and the HS, ;(10) = 4.08, p < .005, but no significant change on the DAS, J(10) = 2.48, ns, or the CBQ, f(10) = 1.90, ns. At posttreatment, there was no significant difference, F(l, 37) = .33, ns, in depression severity as measured by the MHRSD between patients in the standard treatment (M = 8.11, SD = 6.72) and patients who additionally received CT (M= 6.64, SD = 8.47). The M ANOVA comparing patients in the two treatment conditions on the measures of cognitive distortion, however, was statistically significant, F(4, 34) = 4.61, p < .005. The results from the one-way ANOVAs indicate that patients who additionally received CT reported less hopelessness, F(l, 37) = 13.38, p < .001, and fewer cognitive biases, ^(1, 37) = 5.12, p < .05, than did patients in the standard treatment (Table 2). Six-Month Follow-Up At the 6-month follow-up, there was no significant difference, F(l, 37) = .06, ns, in depression severity as measured by the MHRSD between patients in the standard treatment (M =
Twelve-Month Follow-Up At the 12-month follow-up, there was no significant difference, F(i, 37) = .02, ns, in severity of depression as measured by the MHRSD between patients in the standard treatment (M = 6.79, SD = 7.19) and patients who received CT in addition to the standard treatment (M= 6.46, SD = 7.44). The MANOVA testing for differences between the two treatments on measures of cognitive distortion, however, was significant, F(4, 34) = 2.96, p < .05. As can be seen in Table 2, one year following therapy, patients who received the additional CT continued to report less hopelessness, F(\, 37) = 6.41, and fewer cognitive biases, F(l, 37) = 6.67, both ps < .05, than did patients who received only the standard treatment. Discussion Our study was conducted to test the specificity of treatmentinduced cognitive change for CT by comparing treatment changes on four measures of cognitive distortion for depressed inpatients receiving pharmacotherapy alone with patients receiving pharmacotherapy plus CT. We expanded on previous research in this area by using standardized assessment questionnaires that measure surface and core cognitive distortions and by making comparisons between the two treatment conditions during the follow-up period (in addition to posttreatment comparisons). We hypothesized that patients in both treatments would endorse fewer dysfunctional cognitions following therapy. We also predicted that patients who received CT in addition to the standard treatment would endorse fewer dysfunctional cognitions than patients who received only the standard treatment.
Table 1 Demographic and Depression Characteristics for Depressed Inpatient Sample Characteristic Age (in years) Female Attended college Married Modified Hamilton Rating Scale for Depression Beck Depression Inventory Age of onset (in years) Recurrent depression No. of previous episodes Dysthymia diagnosis Melancholia diagnosis Psychotic depression diagnosis
M
SD
34.69
10.95
22.44 27.08 25.03
3.95 7.75 11.29
7.35
8.95
84.60 48.70 71.80
86.80 49.09 27.27 9.09
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Table 2 Means and Standard Deviations on Cognitive Distortion Measures Pretreatment
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Measure Automatic Thoughts Questionnaire Standard Tx Cognitive Tx Hopelessness Scale Standard Tx Cognitive Tx Cognitive Bias Questionnaire Standard Tx Cognitive Tx Dysfunctional Attitude Scale Standard Tx Cognitive Tx
Posttreatment
6 months
12 months
SD
M
SD
M
SD
61.89 45.36
33.78 28.73
62.04 47.64
33.68 33.58
58.04 42.64
32.44 16.94
5.12 5.02
8.71 1.36
6.59 0.92
7.75 3.00
6.51 4.47
7.54 2.27
6.68 2.45
3.00 1.36
3.12 1.36
2.71 0.64
2.93 1.21
2.96 0.82
2.98 0.98
1.93 0.27
2.07 0.65
151.93 143.27
44.18 37.35
138.82 114.73
50.92 22.72
138.36 102.18
46.48 36.96
137.57 109.91
48.69 41.12
M
SD
100.93 97.09
25.49 27.10
12.43 7.82
Note. Tx = treatment.
The first hypothesis was generally confirmed. Compared with their pretreatment scores, patients in both treatments reported significantly less hopelessness and fewer automatic thoughts at the end of treatment. These findings are consistent with earlier studies (e.g., Blackburn & Bishop, 1983; Rush et al, 1982; Simons et al., 1984). Hollon et al. (1987) have proposed a number of causal mediational models of cognitive change within comparative treatment studies that may account for these findings. The models differ in the role that is placed on causal specificity/nonspecificity and consequential specificity/ nonspecificity. These authors propose that cognitive change is a causal mediator of change in depression forCT but not pharmacotherapy (causal specificity) and that change in depression for both treatment conditions produces consequent changes in cognitions (consequential nonspecificity). Future research using structural or causal modeling strategies is necessary to evaluate this proposed mediational model of change. Although the two treatments evidenced significant change on the measures of hopelessness and automatic thoughts, there were no significant pretreatment to posttreatment changes on measures of dysfunctional attitudes or cognitive biases for either treatment. This may be explained by the nature of the measures. The HS and ATQ are often conceptualized as measures of surface cognition, whereas the DAS and CBQ are conceptualized as measures of core cognitive functioning. As such, it would be expected that the treatments would have a greater impact on reducing surface cognitive distortion than core cognitive distortion. The lack of significant pretreatment to posttreatment change on the DAS and CBQ may also be explained in part by the small sample size and the accompanying lack of power to identify changes in these measures following treatment. The second hypothesis was also generally confirmed. Compared with patients who received only the standard treatment, patients who additionally received CT reported less hopelessness and fewer cognitive biases at posttreatment and at 6-month and 12-month follow-up assessments and fewer dysfunctional
attitudes at the 6-month follow-up. These differences between treatments were significant even though the two treatments did not differ in concurrent depression severity. These findings argue against the rival hypothesis that, compared with patients who received the standard treatment only, patients who received the additional CT would report less cognitive distortion due to greater state-dependent reduction in cognitive distortion produced by greater change in depression. To further rule out this alternative hypothesis, the significant univariate tests were reanalyzed, while statistically controlling for concurrent depression. The results of these analyses of covariance were consistent with the results of the ANOVAs. When level of depression was statistically controlled for, the addition of CT to the standard treatment resulted in less hopelessness and fewer cognitive biases at posttreatment and at the 6- and 12-month followups and fewer dysfunctional attitudes at the 6-month follow-up. There was, however, significant (p < .05) heterogeneity of regression for the posttreatment and 12-month follow-up assessments on the HS, so these specific results should be interpreted with caution. The central finding that CT, in comparison with standard pharmacotherapy, produces specific effects on measures of cognitive distortion strengthens the probability that CT possesses unique and effective therapy elements (Beckham & Watkins, 1989). In addition to differences on measures of cognitive distortion observed between treatments at posttreatment, our study is the first to document that these differences were maintained at follow-up. According to cognitive theory of depression, individuals who endorse fewer cognitive distortions are less likely to become depressed when they encounter negative events in their lives. Consequently, the current finding that patients who additionally received CT endorsed fewer cognitive distortions at posttreatment and follow-up than patients who received only the standard treatment may help to explain why CT has recently been shown to result in lower relapse rates during follow-up. Significant differences between treatment conditions were
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SPECIFIC EFFECTS ON DYSFUNCTIONAL COGNITIONS found on all measures except the ATQ. Results from past studies using the ATQ have suggested that it correlates highly with depressive severity and may be considered a state-dependent measure (e.g., Dobson & Shaw, 1986; Dohr, Rush, & Bernstein, 1989). As such, it may be expected to be less sensitive to between-groups treatment differences in cognitive distortion that are independent of depression severity. In the current study, we compared the impact of adding a CT component to a standard pharmacological inpatient treatment. We were unable, however, to test for differences between CT alone and the standard treatment on measures of cognitive distortion over time, and future research is needed to examine these comparisons. Similarly, the results were obtained with depressed inpatients, and further research is needed to determine whether the results can be generalized to depressed outpatients. Finally, the current study was conducted before the development of competency rating scales for CT. Although the CT sessions were closely supervised, and although the therapist was an experienced CT therapist and the outcome was similar to other clinical trials of CT (Miller, Norman, & Keitner, 1989; Miller, Norman, Keitner, et al., 1989), the current results cannot be generalized to all CT therapists who meet acceptable criteria for CT competency until the results are replicated with such a group of therapists. The obtained results do, however, suggest that future research examining specificity of cognitive change within CT should include a comprehensive assessment of cognitive distortion (including psychometrically established measures of surface and core dysfunctional cognitions) assessed during follow-up, in addition to posttreatment comparisons.
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Received March 26,1990 Revision received August 30,1990 Accepted August 31,1990 •
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