LONDON EAST-ANGLIA RANDOMIZED CONTROLLED TRIAL OF COGNITIVE-BEHAVIORAL THERAPY FOR PSYCHOSIS .2. PREDICTORS OF OUTCOME

Background Despite growing evidence of the effectiveness of cognitive behavioural therapy (CBT) for psychosis, typically only about-50% of p atients show a positive response to treatment. This paper reports the first comprehensive investigation of factors which predict treatment o utcome. Method In a randomised controlled trial of CBT for medication- resistant psychosis (see Part I) measures were taken at baseline of de mographic, clinical and cognitive variables. Changes overtime were ass essed on the Brief Psychiatric Rating Scale and the relationship betwe en potential predictor variables and outcome was investigated using an alysis of variance and covariance. Results A number of baseline variab les were identified as predictors of good outcome in the CBT group. Ke y predictors were a response indicating cognitive I flexibility concer ning delusions (P=0.005) and the number of recent admissions (P=0.002) . Outcome was less predictable in the control group and was not predic ted by any cognitive variable. Conclusions Good outcome is strongly pr edicted in patients with persistent delusions by a cognitive measure, while this was not the case in controls. Thus we argue that positive o utcome in CBT is due in part-to specific effects on delusional thinkin g.