Jun 19 2014
By Eleanor McDermid, Senior medwireNews Reporter
The COMMAND trial shows that cognitive behaviour therapy (CBT) can bring about a “clinically meaningful” reduction in the rate at which patients comply with command hallucinations.
“We believe that the results of this trial represent an important advance in the treatment of individuals with a high risk of committing harm to themselves or others”, say lead researcher Max Birchwood (University of Warwick, UK) and team.
Therapy was based on the theory that patients with schizophrenia obey command hallucinations believing the voice to have harmful intent and “crucially to have the power to deliver the threat.” CBT therefore aimed to challenge and weaken patients’ belief in the power of the voices they heard.
The 197 patients who completed the study had a history of harmful command hallucinations, and of harm to self or others or major social transgressions. At baseline, 84% of the participants were rated as fully compliant to command hallucinations on the Voice Compliance Scale (VCS), while 16% were partly compliant or appeasing.
The 98 patients assigned to CBT received an average of 19 sessions spread across 9 months, with 81% completing all planned therapy (12% did not attend any sessions). During the 9 months of treatment, 48% of the CBT group complied fully with command hallucinations compared with 55% of the 99 patients assigned to receive usual care. This equated to a nonsignificant odds ratio of 0.74 in favour of CBT.
At 18 months – 9 months after completion of CBT – the corresponding rates of full compliance on the VCS were 28% versus 46%, giving a significant odds ratio of 0.45. The fact that compliance fell in both groups suggests that the patients were “identified at baseline at the peak of compliance and distress”, write the researchers in The Lancet Psychiatry.
Of note, Voice Power Differential Scale total and power ratings were lower in the CBT than the usual care group at 9 and 18 months, but not at baseline, giving a significant treatment effect. This suggests that changes in patients’ perception of the voices’ power relative to their own may have reduced their desire to comply.
In a commentary accompanying the study, Raymond Cho (University of Texas Health Science Center at Houston, USA) describes the findings “very promising”.
But he adds that “elucidation of both the mechanism and time course of the treatment effects will be crucial for any attempts at translation of the approach to actual clinical practice in a practicable and cost-efficient manner.”
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