BACKGROUND A series of small, mainly uncontrolled, studies have suggested that techniques adapted from cognitive-behavioural therapy (CBT) for depression can improve outcome in psychosis, but no large randomised controlled trial of intensive treatment for medication-resistant symptoms of psychosis has previously been published.

METHOD Sixty participants who each had at least one positive and distressing symptom of psychosis that was medication-resistant were randomly allocated between a CBT and standard care condition (n = 28) and a standard care only control condition (n = 32). Therapy was individualised, and lasted for nine months. Multiple assessments of outcome were used.

RESULTS Over nine months, improvement was significant only in the treatment group, who showed a 25% reduction on the BPRS. No other clinical, symptomatic or functioning measure changed significantly. Participants had a low drop-out rate from therapy (11%), and expressed high levels of satisfaction with treatment (80%). Fifty per cent of the CBT group were treatment responders (one person became worse), compared with 31% of the control group (three people became worse and another committed suicide).

CONCLUSIONS CBT for psychosis can improve overall symptomatology. The findings provide evidence that even a refractory group of clients with a long history of psychosis can engage in talking about psychotic symptoms and their meaning, and this can improve outcome.