The efficacy of nabilone, a synthetic cannabinoid, in the treatment of PTSD-associated nightmares: A preliminary randomized, double-blind, placebo-controlled cross-over design study.

Objective: Investigate the efficacy of nabilone capsules (NAB) in reducing the frequency and intensity of nightmares in subjects with PTSD.

Patients And Methods: Canadian male military personnel with PTSD, who despite standard treatment continued to experience trauma-related nightmares, received double-blind treatment with 0.5mg NAB or placebo (PBO), and then titrated to the effective dose (nightmare suppression) or reaching a maximum of 3.0mg. Subjects were followed for 7 weeks and then, following a 2-week washout period, were titrated with the other study treatment and followed for an additional 7 weeks. The modified intent-to-treat (mITT) population, which included all treated subjects that met inclusion/exclusion criteria, was analyzed.

Results: Ten subjects were included in the mITT population. The mean reduction in nightmares as measured by the CAPS Recurring and Distressing Dream scores were -3.6 ± 2.4 and -1.0 ± 2.1 in the NAB and PBO groups, respectively (p=0.03). Mean global improvement as measured by the Clinical Global Impression of Change (CGI-C) was 1.9 ± 1.1 (i.e. much improved) and 3.2 ± 1.2 (i.e. minimally improved) in the NAB and PBO groups, respectively (p=0.05) Five out of 10 (50%) were much improved on NAB versus 1 out of 9 (11%) on PBO. Results for the General Well Being Questionnaire (WBQ) were 20.8 ± 22 and -0.4 ± 20.6 in the NAB and PBO groups, respectively (p=0.04). The proportion of subjects who experienced a treatment-related occurrence of adverse events was 50% in the NBO group and 60% in the PBO group. No event was severe nor resulted in a drop-out. This study is registered with Health Canada.

Conclusion: In this small sample NAB provided significant relief for military personnel with PTSD, indicating that it shows promise as a clinically-relevant treatment for patients with nightmares and a history of non-response to traditional therapies. These findings need to be replicated in a larger cohort. There is a need for further exploration of the effect of nabilone on other symptoms of PTSD such as re-experiencing, hyper vigilance and insomnia.