Patients' comprehension and skill usage as a putative mediator of change or an engaged target in cognitive therapy:...

The skills that patients learn in cognitive therapy (CT) and use thereafter may mediate improvement in depression during and after intervention.

We used a sequential, three-stage design: acute phase (523 outpatients received 12-14 weeks of CT); 8-month experimental phase (responders at higher risk were randomized to continuation phases: C-CT, C-fluoxetine or C-pill placebo); and 24 months of longitudinal, post-treatment follow-up. Path analyses estimated mediation by skill measured by the Skills of Cognitive Therapy (SoCT: Patient and Observer [Therapist] versions).

Better SoCT scores predicted lower depressive symptoms both in CT and C-CT. In CT depressive symptoms did not predict subsequent changes in skills. During CT and C-CT, when averaged across patients and therapists, skills predicted subsequent decreases in depressive symptoms.

Generalization of findings may be limited by the trial's methodology.

Further rigorous investigation of the role of patient CT skills stands to increase understanding of mediators of change or engaged targets in psychosocial intervention.