How does cognitive therapy prevent relapse in residual depression? Evidence from a controlled trial

This study examined the cognitive mediation of relapse prevention by cognit ive therapy (CT) in a trial of 158 patients with residual depression. Score s based on agreement with item content of 5 questionnaires of depression-re lated cognition provided no evidence for cognitive mediation. A measure of the form of response to those questionnaires, the number of times patients used extreme response categories ("totally agree" and "totally disagree"), showed significant and substantial prediction of relapse, differential resp onse to CT, and conformity to mediational criteria. CT reduced relapse thro ugh reductions in absolutist. dichotomous thinking style. CT may prevent re lapse by training patients to change the way that they process depression-r elated material rather than by changing belief in depressive thought conten t.