Cannabis: are there any benefits?

Cannabis has been used as a medicine for millennia. Prohibition in the mid-20th century precluded early scientific investigation. ‘Cannabis’ describes three separate forms – herbal cannabis, ‘hemp’ products, pharmaceutical-grade regulated cannabinoid-based medical products (CBMP). In Australia, CBMP became available for prescription in November 2016. Herbal cannabis with Δ9-tetrahydrocannabinol (THC), which is illegal, and cannabidiol (CBD) in herbal extracts, are both unregulated and unreliable sources of cannabinoids. The endocannabinoid system (ECS), delineated in the late 1990s, has increased the understanding and interest in research for appropriate clinical indications. The ubiquitous ECS has homeostatic and anti-inflammatory effects and comprises cannabinoid receptors, endocannabinoids and degrading enzymes. Phytocannabinoids are partial agonists of the ECS. In pre-clinical studies, THC and CBD produce beneficial effects in chronic pain, anxiety, sleep and inflammation. Systematic reviews often conflate herbal cannabis and CBMP, confusing the evidence. Currently large randomised controlled trials are unlikely to be achieved. Other methodologies with quality end-points are required. Rich, valuable high-quality real-world evidence for the safe and effective use of CBMP provides an opportunity to examine benefits and potential harms. Evidence demonstrates benefit of CBMP in multiple sclerosis, chronic neuropathic pain, chemotherapy induced nausea and vomiting, resistant paediatric epilepsy, anxiety and insomnia. CBMP are well tolerated with few serious adverse events. Additional clinical benefits are promising in many other resistant chronic conditions. Pharmaceutical grade prescribed CBMP has proven clinical benefits and provides another clinical option in the physician's pharmacopeia.