Medicinal cannabis in the management of anxiety disorders: A systematic review

Background: With rising anxiety disorder diagnoses, many individuals are seeking alternatives to standard pharmacotherapies, like medicinal cannabis. This systematic review focuses exclusively on anxiety-related disorders and examines a wide range of cannabis-based preparations and interventions. Method: We searched MEDLINE, EMBASE, CINAHL, and PsycInfo (October–December 2023) for peer-reviewed empirical studies, excluding case series, case studies, and review papers. Inclusion criteria were studies on adults (18+ years) diagnosed with anxiety-related disorders, examining the efficacy or effectiveness of medicinal cannabis. Studies on recreational cannabis or cannabis-use-disorder were excluded. The MASTER and QualSyst tools were used to assess bias. Results: Fifty-seven studies met the inclusion criteria: 40 % cohort (n = 23), 30 % randomised controlled trials (n = 17), 18 % cross-sectional (n = 10), 12 % qualitative or other designs (n = 7). The MASTER scale revealed a high risk of bias, with a mean score of 62.9 (out of 100) due to inadequate reporting. Among the 13 highest-quality studies, 70 % (n = 9) reported a positive improvement for disorders including generalised anxiety disorder (GAD), social anxiety disorder (SAD), and post-traumatic stress disorder (PTSD). 30 % (n = 4) reported a negative result for conditions like obsessive-compulsive disorder, trichotillomania, test anxiety and SAD. Over 90 % of all studies, including lower quality studies, reported positive outcomes for CBD and THC-based cannabis. However, 53 % (n = 30) either omitted, or included self-reported data on either form and/or dosage. Conclusion: Medicinal cannabis demonstrates potential in reducing anxiety symptoms, but the long-term benefits and overall impact on quality of life remain unclear. Further high-quality, longitudinal research with standardised dosing is needed.