RCTs (total n = 101), designed to test the efficacy of smoked marijuana for at least five days in treating neuropathic pain, have been positive (18–20), with additional evidence from challenge studies. Additionally, large trials testing the efficacy of nabiximols or an oral cannabis extract in neuropathic pain have also shown benefit (17, 21, 22). Robust clinical evidence (i.e., large RCTs) for other indications is generally lacking (Table 2). Preclinical research, however, is promising: cannabinoids have demonstrated anti-inflammatory (23) and anticonvulsant (24) properties. Furthermore, THC and CBD have been shown to enhance extinction learning, a process critical in the treatment of PTSD (39, 40). Evidence also suggests that cannabinoids may transiently lower intraocular pressure, suggesting promise in the treatment of glaucoma (41). However, further research is needed to examine whether these preclinical findings translate into clinical efficacy and to explore the potential risks of smoked or edible marijuana compared to oral/nasal cannabis extracts.
