The mechanism and time course of sudden gains in behavioral activation treatment for depression.

摘要

Behavioral activation (BA) trains depressed clients to engage in more positive activities in order to increase their experience of pleasure and accomplishment, thereby reducing depression. Recent research suggested that BA might be as effective in treating depression as current leading treatments, such as cognitive-behavioral therapy (CBT) and antidepressant medication (Jacobson, Dobson, Truax, et al., 1996; Dimidjian, Hollon, Dobson, et al., 2006). Sudden gains are large symptom improvements concentrated in one between-session interval, and they were first discovered in CBT for depression (Tang & DeRubeis, 1999). The present project investigated sudden gains, their relationship to treatment outcomes, and their mechanism in the BA treatment of depression.;In study 1, we discovered sudden gains in the Jacobson et al. (1996) BA sample. As in previous sudden gain studies, we found that BA sudden gains predicted lower depression levels at treatment termination, but we showed this association using both a self-report (Beck Depression Inventory) and a clinician-rated (Hamilton Rating Scale for Depression) depression outcome measure. Sudden gain treatment responders also showed significantly lower relapse rates than non-sudden-gain responders during a 24-month follow-up period. These findings suggested that BA sudden gains were enduring improvements in clients' depression and not transient random symptom fluctuations.;In study 2, we investigated the mechanism of BA sudden gains. We found that mechanisms specific to BA correlated strongly with these sudden gains, namely the client's within-session agreement to behavior change and the number of positive activities completed between sessions. Within-session cognitive changes were not significantly related to BA sudden gains. Therapeutic alliance increased following and not directly prior to sudden gains, similar to findings in Tang and DeRubeis (1999). But BA sudden gainers also experienced a better therapeutic alliance than non-sudden-gainers at session 2, supporting the importance of this common factor in laying the early groundwork for later depression improvement. The implications of these results on helping us understand BA's mechanisms and potentially helping improve the treatment's effective delivery are discussed.