Abstract
Psychotherapy's equivalence paradox refers to clients achieving similar degrees of overall improvement in different treatment approaches, despite the non-equivalent processes. The current intensive qualitative study described and compared how different processes brought about their respective outcomes in one case of client-centred therapy (CCT) and one of cognitive-behaviour therapy (CBT). The assimilation model of psychotherapeutic change was used to compare processes of change and patterns of improvement in these two demographically and diagnostically similar clients, who had equally favourable outcomes on post-treatment measures. We applied the method of assimilation analysis to both therapies, and compared the assimilation account of client change with the theoretical models used in the two treatments.