Cannabis is increasingly available for the treatment of chronic
pain, yet its efficacy remains uncertain. This systematic review published in Annals of internal medicine
assessed the benefits of plant-based cannabis preparations for treating chronic pain in adults and the harms of cannabis use in chronic pain
and general adult populations. From 27 chronic pain trials, there is low-strength evidence that cannabis alleviates neuropathic pain in
some patients, but insufficient evidence exists for other types of chronic pain. According to 11 systematic reviews and 32 primary studies,
harms in general population studies include increased risk for motor vehicle accidents, psychotic symptoms, and short-term cognitive
impairment. Present research is limited by: few methodologically rigorous trials; cannabis formulations studied may not reflect commercially
available products; and few trials of older, chronically ill populations and patients who use cannabis heavily.