Cognitive analytic therapy: a review of the outcome evidence base for treatment.

PURPOSE This study reviews the quality of the extant outcome evidence for cognitive analytic therapy (CAT) to inform clinical practice and to stimulate a future CAT research strategy. METHOD An electronic search identified CAT efficacy and effectiveness studies and these were subject to systematic review. The methodological quality of studies meeting inclusion criteria were appraised using two validated research study quality checklists and studies were fitted to an established model of psychotherapy evaluation. RESULTS Twenty-five outcome studies met the inclusion criteria, including five randomized controlled trials. The CAT evidence base is predominated by small-scale practice-based studies, in typically complex and severe clinical populations - 44% were focal to the treatment of personality disorder. Although the quality of extant CAT evidence is generally sound (52% of studies were high quality), the depth and breadth of the evidence base is currently limited. Where comparisons with other modalities are available, CAT appears largely equivocal. CONCLUSIONS Cognitive analytic therapy is a popular and promising intervention for complex presentations. However, the evidence base currently lacks wider credibility due to having largely bypassed the rigours of the controlled phase of the hourglass model of psychotherapy evaluation. There is a particular need for further CAT outcome research with common mental health problems. PRACTITIONER POINTS CAT can be an effective intervention across a range of mental health difficulties. Consider a 24-session CAT contract for those patients presenting with complex and severe difficulties. Practice research networks could make a significant contribution to the CAT evidence base.