An Examination of the Process of Symptom Change in Behavioral Activation and Cognitive Therapy for Depression

Cognitive therapy (CT) employs both behavioral and cognitive methods to promote positive changes in depression. Questions remain, however, about the mechanisms of change associated with CT. Further, the recent development of Behavioral Activation (BA) as a distinct alternative model for treating depression leads to the possibility that these two different techniques cause different processes of change. To answer these questions, two groups of depressed patients, one which received behavior activation only and one which received the complete cognitive therapy protocol, were compared through the analysis of change of different symptoms on the Beck Depression Inventory (BDI). Session by session BDI scores of two groups from the data collected for Jacobson et al''s (1996) study, were used as the data set for the current study. The results revealed that although both treatments achieved equal overall outcomes, symptoms of depression had different response patterns. Curve estimation and effect size calculations also showed that although the magnitude of symptom change was comparable for many of the items on the BDI, there were several items where either CT or BA had stronger effects. The implications of these results are discussed with respect to the utility of measuring symptom change in outcome studies for depression. It is suggested that these results imply different mechanisms of change in BA and CT, and the possibility that clinicians might target more on less responsive symptoms in either BA or CT, to maximize treatment outcome. Methodological limitations of the study are presented, and avenues for further research into symptom change in the treatment of depression are presented.