Few patients have access to cognitive behaviour therapy for psychosis (CBTp) even though at least 16 sessions of CBTp is recommended in treatment guidelines. Briefer CBTp could improve access as the same number of therapists could see more patients. In addition, focusing on single psychotic symptoms, such as auditory hallucinations (‘voices’), rather than on psychosis more broadly, may yield greater benefits.
This pilot RCT recruited 28 participants (with a range of diagnoses) from NHS mental health services who were distressed by hearing voices. The study compared an 8-session guided self-help CBT intervention for distressing voices with a wait-list control. Data were collected at baseline and at 12 weeks with post-therapy assessments conducted blind to allocation. Voice-impact was the pre-determined primary outcome. Secondary outcomes were depression, anxiety, wellbeing and recovery. Mechanism measures were self-esteem, beliefs about self, beliefs about voices and voice-relating.
Recruitment and retention was feasible with low study (3.6%) and therapy (14.3%) dropout. There were large, statistically significant between-group effects on the primary outcome of voice-impact (d = 1.78; 95% CIs: 0.86–2.70), which exceeded the minimum clinically important difference. Large, statistically significant effects were found on a number of secondary and mechanism measures.
Large effects on the pre-determined primary outcome of voice-impact are encouraging, and criteria for progressing to a definitive trial are met. Significant between-group effects on measures of self-esteem, negative beliefs about self and beliefs about voice omnipotence are consistent with these being mechanisms of change and this requires testing in a future trial.