Differential change in integrative psychotherapy: a re-analysis of a change-factor based RCT in a naturalistic setting.

General Psychotherapy (GPT; Grawe, 1997) is a research-informed psychotherapy that combines cognitive-behavioral and process-experiential techniques and that assumes motivational clarification and problem mastery as central mechanisms of change. To isolate the effect of motivational clarification, GPT was compared to a treatment that proscribed motivational clarification (General Psychotherapy Minus Clarification, GPT-C) in a randomized-controlled trial with 67 diagnostically heterogeneous outpatients. Previous analyses demonstrated equal outcomes and some superiority for highly avoidant patients in GPT. Re-analyses using causal-analytic methods confirmed equal changes, but also showed superior effects for GPT in highly symptomatic patients. Results are discussed regarding theory, methodological limitations, and implications for research and practice.