Behav. Res. Thu. Vol. 31, No. 3, pp. 325-330, 1993 OOOS-7967/93 S6.00 + 0.00 Printed in Great Britain. All rights mservcd Copyright 0 1993 Pergamon Press Ltd zyxwvutsrqpon Outcome profiles in the treatment of unipolar depression STEVEN TAYLOR and PETER MCLEAN Department of Psychiatry, University of British Columbia, 2255 Westbrook Mall, Vancouver, EC, Canada V6T 24 I (Received 25 March 1992) Summary-Treatment efficacy is typically evaluated by examining group means and pre-post change scores. Although informative, such analyses may obscure individual or subgroup differences in response (outcome profiles). The present study used two different methods to define treatment outcome profiles- rationally-derived criteria (Frank et al., Archives of General Psychiatry 48, 851-455, 1991) and dynamic clustering-to evaluate four treatments of unipolar depression: behaviour therapy, amitriptyline, psycho- dynamic psychotherapy and relaxation training (attention placebo). The profiling methods yielded similar results. Regardless of treatment, the majority of patients displayed either a recovery or nonremission outcome profile, with relatively few instances of remission followed by a recurrence of depression. These findings challenge the view that any of the treatments are associated with a strong tendency to relapse, at least over the 3-month follow-up period. To further characterize the major outcome profiles, discriminant analysis was performed. Results indicated that recovery and nonremission profiles differed in that the latter was associated with a longer and more severe index episode and greater neuroticism. A number of variables, including family history of depression and therapists’ prediction of outcome, failed to distinguish recovered from unremitted patients. INTRODUCI’ION There are several ways of characterizing treatment efficacy. The most common approach has been to measure the degree of improvement from pre- to post-treatment, and to determine whether these gains are maintained over a given follow-up interval. An important, complementary approach to therapy evaluation is to determine the major outcome profiles for a given type of treatment. That is, what proportion of Ss show treatment outcome patterns such as nonremission, remission without relapse, remission with relapse and so forth? These patterns may be obscured in the analysis of group means. For example, consider a comparison of group means for two treatments. Although the means may suggest that the treatments are of equivalent efficacy, it may be that one treatment yields of two types of treatment outcome-response and nonresponse-whereas the other treatment is moderately effective for all patients. Thus, the identification of major outcome profiles for a given treatment, and the comparison of these profiles with other treatments, enables one to more fully understand the treatment outcome characteristics and patient predictors of response to the various therapies. There is suggestive evidence that behavioural-cognitive therapies are associated with fewer relapses or recurrences than tricyclic phannacotherapy (Hollon, Shelton & Loosen, 1991). This may occur because the former provides patients with skills in adaptive problem-solving and mood-management (Beck, Rush, Shaw % Emery, 1979, McLean, 1976), and suggests that a treatment response-then-recurrence (response -t recurrence) profile is unlikely to be a common outcome pattern for behavioural-cognitive therapies. The question remains as to the proportion of patients showing response + recurrence profiles for other treatments such as the pharmacotherapies. A further question is how the outcome profiles vary with the pre-treatment severity of depression. Elkin et al. (1989) found that tricyclic pharmacotherapy was of comparable efficacy to cognitive-behavioural therapy for mild depression, but that the former was more effective for severe. depression. Recent studies by McLean and Taylor (1992) and Hollon et al. (1989, unpublished, cited in Hollon, Shelton & Loosen, 1991) failed to replicate this finding. McLean and Taylor (1992) found that behaviour therapy was generally more effective than amitriptyline, and both treatments were less efiective for patients who were initially more depressed. These findings suggest that for both treatments, the more depressed patients show a nonresponse profile, whereas the less depressed patients are more likelv to resoond to treatment. While the anal&is of outcome profiles can make an important contribution in understanding treatment outcome characteristics, it has not met with widespread use.. The main reason for this is the lack of consensus about how to define profiles. Currently. there is no consensus regarding the criteria for defining recovery, recurrence or remission of depression (Frank et al., 1991; Prien, Carpenter & Kupfer, 1991). Frank et al. (1991) recommended a set of criteria (described below), although these are arbitrary in nature. Another approach is to empirically determine outcome profiles by means of dynamic clustering (Prochaska, Velicer, Guadagnoli, Rossi & DiClemente, 1991). This is a cluster analytic procedure where the units of clustering are not a collection of variables obtained at a given time. as in conventional cluster analysis, but rather based on the same variable measured at different points in timeTIn this way dynamic outcome typologies can be obtained (Prochaska et al., 1991). Unfortunately, this procedure contains the limitations inherent to all clustering procedures. The main shortcoming is that the cluster solution needs to be cross-validated (Morris, Blashfield & Satx, 1981). Dynamic clustering and the use of the Frank et al. (1991) criteria both have limitations, yet they may yield important information on the patterns of outcome associated with the various treatments for depression. The purpose of the present study was to apply both methods to the analysis of outcome profiles, with a particular emphasis on convergent results. Specifically, our aims were to identify and compare the major outcome profiles for the following treatments for unipolar depressed outpatients: behaviour therapy, psychodynamic psychotherapy, amitriptyline and attention placebo (relaxation training). Treatment effects were examined at post-treatment and 3-month follow-up. The group differences were originally aaT 3Ip-G ,,a