Journal ol Abnormal Psychology 1972, Vol. 79, No. 3, 291-295 PLEASANT EVENTS, ACTIVITY SCHEDULES, AND DEPRESSIONS PETER M. LEWINSOHN 2 AND JULIAN LIBET University of Oregon Three groups of 10 Ss, (depressed, psychiatric controls, and normal controls) were used. The 6s rated their moods and also indicated the number of "pleasant" activities engaged in each day over a period of 30 days. A significant association between mood and pleasant activities was found. There were large individual differences in regard to the magnitude of the correlation between mood and activity, but differences between groups failed to attain statistical significance. The results are interpreted as consistent with the major tenet of the behavioral theory of depression, that is, that there is an association between rate of positive reinforce- ment and intensity of depression. The investigation was conducted within the context of a behamorally oriented clincial-re- search program on depression. A key tenet of the approach is the assumption that a low rate of positive reinforcement constitutes a critical antecedent condition for the occurrence of de- pressive behaviors. In effect, the behavioral theory requires the onset of depression be accompanied by a reduction in positive rein- forcement, that intensity of depression covary with rate of positive reinforcement, and that improvement be accompanied by an increase of positive reinforcement. As an outgrowth of the research program, which has been described elsewhere (Lewin- sohn, Shaffer, & Libet, 1969), it has become evident that a low rate of behavior constitutes an extremely important clinical aspect of de- pression (Libet & Lewinsohn, in press). Con- sistent with the major premises of the theory, the principal goal of treatment is to restore an adequate schedule of positive reinforcement for the patient by altering the level, the quality, and the range of his activities and interpersonal interactions. We have become increasingly im- pressed with the clincial utility of activity schedules as a technique for (a) assessing what events or activities are potentially reinforcing for the patient; (6) focusing for the patient his low rate of emitting the behaviors which are positively reinforcing for him; (c) denning an increase in such activities as an explicit goal 1 This investigation was supported in part by United States Public Health Service Grant MH 19784-01 from the National Institute of Mental Health. 2 Requests for reprints should be sent to Peter M. Lewinsohn, Department of Psychology, University of Oregon, Eugene, Oregon 97403. for treatment; and (d) objectively measuring behavior change. The use of activity schedules with depressed patients has been illustrated in earlier publi- cations (Johansson, Lewinsohn, & Flippo, 1971; Lewinsohn, Weinstein, & Shaw, 1969). An activity schedule is constructed by using events judged by the patient himself to be pleasant for him. The patient is subsequently asked at the end of each day to indicate which activities he engaged in and to rate his mood on the Depression Adjective Check List (Lubin, 1965). Data collected from eight de- pressed patients 3 ' 4 revealed a statistical associ- ation between these two variables, the patient's mood being most dysphoric on days during which he emitted very few of the activities on his list. The present study was designed to test the general hypothesis that intensity of depression is a function of amount of positive reinforce- ment. The empirical prediction calls for a correlation between ratings of an individual's mood and the number of "pleasant" activities engaged in by him. The direction of causation can be questioned. It is, on a priori grounds, equally plausible for a person to be less depressed following an increase in pleasant activities as it is to assume an increase in pleasant activities to follow his being less depressed. Data were collected to 3 The authors wish to thank Douglas MacPhillamy and Bob Dittrich, who acted as therapists for some of the cases, and Michael Graf for his assistance with the data collection. 4 These and other materials are available from the authors. Please send requests to Peter M, Lewinsohn, Department of Psychology, University of Oregon, Eugene, Oregon 97403. 291