The Intricate Influence of the Placebo Effect on Medical Cannabis and Cannabinoids

The botanical drug cannabis flos (inflorescence of Cannabis sativa L.) has a unique popular status as being a potent recreational drug and bona fide universal remedy (panacea). Generally, cannabinoids exert therapeutic effects in a broad range of pathophysiologies related to inflammation, pain, metabolic and stress-related conditions in preclinical animal models. However, the translation of such data to humans still lacks an evidence-based foundation. Motivated by the booming cannabis manufacturing industry and the increasing worldwide self-therapy by patients, there are cumulative accounts about broad therapeutic effects of cannabis and legal cannabinoids like cannabidiol (CBD) beyond statistical evidence. The numerous affirming anecdotal reports by patients pose a challenge to physicians and legal authorities. Moreover, the lack of standardization of cannabis products and widely missing randomized double-blind placebo-controlled clinical trials largely hinder the scientific assessment of medical cannabis in humans. Given the recent insight that the endocannabinoid system is mediating, at least in part, a placebo effect, psychoactive cannabis and cannabinoids could exert complex neuropharmacological actions. As discussed in this commentary, the meaning response may play a role in the broad palliative and therapeutic effects of medical cannabis unprecedented by other phytopharmaceuticals.