The MRC command trial: Results of a multi-centre, randomised controlled trial of cognitive therapy to prevent harmful compliance with command hallucinations

Abstract

Background: Acting on command hallucinations in psychosis can have serious consequences for self and others and is a major source of clinical and public concern. There are no evidence-based treatment options to reduce this risk behaviour. Our new treatment uses cognitive therapy to challenge the perceived power of voices to inflict harm on the voice hearer if commands are not followed, thereby motivating compliance. Methods: COMMAND is a pragmatic, single blind, intention-to-treat, randomized controlled trial comparing Cognitive Therapy for Command Hallucinations (CTCH) + Treatment as Usual (TAU) with TAU alone. Eligible participants were from UK mental health services reporting command hallucinations for at least 6 months leading to major episodes of harm to self or others. The primary outcome was harmful compliance and secondary outcomes: beliefs about voices' power and related distress; psychotic and depression symptoms. Outcome was assessed at 9 and 18 months. The trial was registered under controlled-trials.com (ISRCTN62304114). Findings: 197 participants were randomly assigned (98 to CTCH+TAU and 99 to TAU), representing 81.4% of eligible individuals. At 18 months, 46% of the TAU participants fully complied compared to 28% of those receiving CTCH+TAU (odds ratio = 0.45, 95% confidence interval 0.23 to 0.88, p=0.021). The estimate of the treatment effect common to both follow-up points was 0.57 (95% confidence interval 0.33 to 0.98, p=0.042). The total estimated treatment effect for voice power common to both time points was -1.819 (95% confidence interval, -3.457 to -0.181, p=0.03). Treatment effects for secondary outcomes were not significant. Interpretation: The trial demonstrated a large and significant reduction in harmful compliance, in parallel with the singular target of treatment, the perceived power of the voice. We believe this marks a significant breakthrough in this high risk group which consumes much clinical and public concern. Funding: Medical Research Council UK and the National Institute for Health Research.