Acute and chronic effects of medicinal cannabis use on anxiety and depression in a prospective cohort of patients new to cannabis.

INTRODUCTION

Medicinal cannabis has mixed evidence for treating anxiety and depression, yet patients frequently use it as a treatment. This observational study evaluated the effects of medicinal cannabis initiation in adults with clinically significant anxiety and/or depression over a 6-month period.

METHODS

Adults with clinically significant anxiety and/or depression initiating medicinal cannabis use in Maryland, USA completed ecological momentary assessment (EMA) and longitudinal follow-up evaluations. Hospital Anxiety and Depression Scale (HADS) assessments were completed at baseline and 1, 3, and 6 months after medicinal cannabis initiation. EMA measures were completed at baseline and daily for 8 weeks after cannabis initiation with measures collected before each cannabis use and at time of expected peak effect. Changes in anxiety and depression were evaluated using linear mixed effect models.

RESULTS

Significant decreases from baseline in anxiety and depression were observed, with mean scores dropping below clinically significant levels within three months of initiation. EMA data indicated that most participants selected THC-dominant cannabis and acute reductions in anxiety, depression, and perceived driving ability along with increased ratings of feeling "high". Acute effects were dose-dependent: 10-15 mg of oral THC and at least 3 puffs of vaporized cannabis yielded the most robust reductions in anxiety and depression.

CONCLUSIONS

Initiation of THC-dominant medicinal cannabis was associated with acute reductions in anxiety and depression, and sustained reductions in overall symptom severity over a 6-month period. Controlled clinical trials are needed to further investigate the efficacy and safety of medicinal cannabis for acute anxiety and depression symptom management.