The Therapeutic Potential and Usage Patterns of Cannabinoids in People with Spinal Cord Injuries: A Systematic Review

BACKGROUND: People with spinal cord injuries (SCI) commonly experience pain and spasticity; limitations of current treatments have generated interest in cannabis as a possible therapy. OBJECTIVES: We conducted this systematic review to: 1) examine usage patterns and reasons for cannabinoid use, and 2) determine the treatment efficacy and safety of cannabinoid use in people with SCI. METHODS: PubMed, Embase, Web of Science and Cumulative Index to Nursing and Allied Health Literature databases were queried for keywords related to SCI and cannabinoids. RESULTS: 7,232 studies were screened, and 34 were included in this systematic review. Though 26 studies addressed cannabinoid usage, only 8 investigated its therapeutic potential on outcomes such as pain and spasticity. The most common method of use was smoking. Relief of pain, spasticity and recreation were the most common reasons for use. A statistically significant reduction of pain and spasticity was observed with cannabinoid use in 83% and 100% of experimental studies, respectively. However, on examination of randomized control trials (RCTs) alone, effect sizes ranged from -0.82 to 0.83 for pain and -0.95 to 0.09 for spasticity. Cannabinoid use was associated with fatigue and cognitive deficits. CONCLUSION: Current evidence suggests that cannabinoids may reduce pain and spasticity in people with SCI, but its effect magnitude and clinical significance are unclear. Existing information is lacking on optimal dosage, method of use, composition and concentration of compounds. Long-term, double-blind, RCTs, assessing a wider range of outcomes should be conducted to further understand the effects of cannabinoid use in people with SCI.