The purpose of this Rapid Response report is to summarize the evidence of clinical efficacy and harms associated with evidence of efficacy and safety of long-term nabilone use in adult populations with PTSD and other chronic conditions. [...] Critical Appraisal of Individual Studies The included systematic review was critically appraised using the AMSTAR tool,8 and randomized studies were critically appraised using Downs and Black Checklist.9 Summary scores were not calculated for the included studies; rather, a review of the strengths and limitations of each included study were described. [...] Summary of Critical Appraisal Based on the AMSTAR assessment, the included systematic review appeared to be rigorous in design in terms of the search strategy and quality assessment,6 with detailed reporting of the characteristics of the included studies and their populations and a narrative summary of results. [...] Three of the RCTs reported limited details about the demographic and clinical characteristics the included patients, and details of adverse events were sparse.7,10,12 Some internal validity items were not met, with lack of detailed reporting of methods of randomization or allocation concealment and adherence to study medication. [...] The remaining three RCTs assessed the efficacy of nabilone for chronic conditions associated with pain or spasticity.7,11,12 In 15 patients with MS-induced neuropathic pain, the efficacy of nabilone was assessed as add on therapy to gabapentin after nine weeks of treatment.7 The intensity of pain improved at a faster rate with nabilone over the nine-week period than with placebo, with visual analo