A Systematic Review of the Clinical Effects of Cannabis and Cannabinoids in Posttraumatic Stress Disorder Symptoms and Symptom Clusters

Objective: Given the high rate of comorbid posttraumatic stress disorder (PTSD) and cannabis use, it is critical that further research be conducted to address the associated benefits and risks of cannabis use in this population. This systematic review evaluated evidence on the effects of cannabis and cannabinoids on PTSD symptoms and PTSD clusters. Data Sources: A systematic search of PubMed, PsycINFO, and EMBASE databases was performed using terms related to cannabis, cannabinoids, and PTSD. Peer-reviewed studies available online in English and published from January 1990 through February 2023 were considered. Study Selection: Included studies were experimental or observational in design, were conducted in cannabis-using patients with PTSD, used validated measures of PTSD, and were published in English. Data Extraction: Extracted information included study aims, study design, sample size and sex, comparator group, cannabis-related characteristics, psychometric instruments, and relevant clinical findings regarding overall PTSD symptoms and cluster symptoms. Results: Fourteen studies were included, 3 in a comorbid PTSD and cannabis use disorder (CUD) sample and 11 in a non-CUD sample. Of the 10 studies examining overall PTSD symptoms in a non-CUD sample, 5 suggested benefits associated with cannabis use and 5 suggested no effect or worsening of symptoms. Four studies reported benefits of cannabis for cluster B- and E-related symptoms in a non-CUD sample. All 3 studies in cannabis-using patients with a comorbid PTSD and CUD diagnosis reported risks for worsening of overall symptoms. Conclusions: This review did not find major benefits of cannabinoids in improving overall PTSD symptoms. Some benefits with regard to cluster B and E symptoms were observed. Some risks with regard to worsening suicidal ideation and violent behavior were also reported. Individuals with a comorbid CUD diagnosis may be at greater risk for negative cannabis-related PTSD outcomes. More experimental studies are needed to determine the causal effects of cannabis and cannabinoids in PTSD.