Abstract Background. The causal impacts of recreational cannabis legalization are not well understood due to the number of potential confounds. We sought to quantify possible causal effects of recreational cannabis legalization on substance use, substance use disorder, and psychosocial functioning, and whether vulnerable individuals are more susceptible to the effects of cannabis legalization than others. Methods. We used a longitudinal, co-twin control design in 4043 twins (N = 240 pairs dis- cordant on residence), first assessed in adolescence and now age 24–49, currently residing in states with different cannabis policies (40% resided in a recreationally legal state). We tested the effect of legalization on...

Objective. Patients with chronic pain, including fibromyalgia (FM), may seek treatments outside of mainstream medicine. Medicinal cannabinoids are popularly advocated for pain relief but with limited evidence for efficacy in FM. The extent of use of cannabinoids in FM is unknown. Methods. We have documented the self-reported prevalence of cannabinoid use in 457 patients with the diagnosis of FM and referred to a tertiary care pain center. We validated the diagnosis of FM and examined the associations of cannabinoid use in these patients. Results. Cannabinoids were being used by 13% of all patients, of whom 80% used herbal cannabis (marijuana), 24% used prescription cannabinoids,...