Controlled clinical trial of cannabidiol in Huntington's disease.
Based on encouraging preliminary findings, cannabidiol (CBD), a major nonpsychotropic constituent of Cannabis, was evaluated for symptomatic efficacy and safety in 15 neuroleptic-free patients with Huntington's Disease (HD). The effects of oral CBD (10 mg/kg/day for 6 weeks) and placebo (sesame oil for 6 weeks) were ascertained weekly under a double-blind, randomized cross-over design. A comparison of the effects of CBD and placebo on chorea severity and other therapeutic outcome variables, and on a Cannabis side effect inventory, clinical lab tests and other safety outcome variables, indicated no significant (p greater than 0.05) or clinically important differences. Correspondingly, plasma levels of CBD were assayed by GC/MS, and the weekly levels (mean range of 5.9 to 11.2 ng/ml) did not differ significantly over the 6 weeks of CBD administration. In summary, CBD, at an average daily dose of about 700 mg/day for 6 weeks, was neither symptomatically effective nor toxic, relative to placebo, in neuroleptic-free patients with HD.
This review finds no evidence that cannabinoids are effective in the improvement of disturbed behaviour in dementia or in the treatment of other symptoms of dementia. More randomized double-blind placebo controlled trials are needed to determine whether cannabinoids are clinically effective in the treatment of dementia.