Time to improve and recover from depressive symptoms and interpersonal problems in a clinical trial

Results from an earlier clinical trial comparing narrative therapy with cognitive-behavioural therapy (Lopes et al., 2013) suggested that narrative therapy is efficacious for depression. However, there were significant differences in symptom reduction on the Beck Depression Inventory-II, favouring cognitive-behavioural therapy, if dropouts were included in the analysis, suggesting that time to recovery or improvement would differ in both treatments. Contrarily, results showed that treatment assignment was not a predictor for differential effect. Using a survival analytic approach, it was found that four sessions were necessary for 50% improvement and 16 sessions for 50% recovery. Additionally, depressive symptoms changes occurred significantly faster than interpersonal changes, again regardless of treatment assignment. These results support previous findings of the dose-response literature and of the phase model of change, with the advantage of being specific to psychotherapy with depressive clients.