Cannabinoids have been suggested for the treatment of numerous conditions, including cancer, vascular, neurodegenerative, and inflammatory diseases.¹ Probably because of the nature of these substances, there is considerable interest in these drugs from the general public, lay media, and politicians. Frequently, the translation of scientific results is overly optimistic and may have contributed to extensive off label usage of cannabis among chronically ill patients. The evidence for therapeutic efficacy in humans is not as yet convincing.

The CAMS study² by Zajicek and colleagues was the first large symptomatic trial of cannabinoids in multiple sclerosis (MS). In this study, 630 patients with stable MS and muscle spasticity were treated with delta-9-tetrahydrocannabinol (THC), cannabis extract or placebo. The main part of the …