Common factors and therapist variability in couple and family therapy treatment outcome

Couple and family therapy (CFT) is at least as effective as individual therapy, and each approach to CFT achieves broadly equivalent results. The most likely explanation for the equivalent effect of CFT approaches is that common factors are responsible for client change, which is consistent with the research on individual psychotherapy. The latest trend in psychotherapy research has been to examine the impact of individual therapists on treatment outcome. Individual therapists are now considered an important variable in outcome and compete with common factors as a proposed mechanism of change. The current empirical psychotherapy research is reviewed to make the case that interpersonal common factors are the core change process in CFT and can also provide a possible explanation of individual therapist effects