The Role of Cannabis in Treating Anxiety: An Update

Michael Van Ameringen; Jasmine Zhang; Beth Patterson; Jasmine Turna

Disclosures

Curr Opin Psychiatry. 2019;33(1):1-7. 

In This Article

Survey Studies

Despite a dearth of evidence and largely contradictory conclusions from empirical research, a substantial number of patients report using cannabis and related products to treat anxiety symptoms or disorders. In a pooled sample from 13 survey studies of cannabis use (N = 6665) 52% reported using cannabis for anxiety, making it the second-most commonly treated symptom, following pain.[34] These results reflect findings from the Australian 2016 Cannabis as Medicine Survey (CAMS-16; N = 1748), where 15% reported anxiety as the main medical condition treated with cannabis, and 51% reported using cannabis to treat anxiety symptoms.[35] Approximately 84% of users across all conditions described their symptoms as 'very much improved' or 'much improved' following cannabis use; whereas, a marginal proportion (less than 1%) of patients reported that cannabis exacerbated their symptoms, and only 1% experienced intolerable side effects.

Recent surveys have also assessed medical cannabis use in samples treating anxiety symptoms and disorders. In a survey of self-identified CBD users (N = 2409), 22.4% of respondents reported treating anxiety with CBD, making it the third-most commonly targeted symptom following chronic pain and joint pain.[36] Of the overall sample, almost 36% of respondents reported that CBD treated their medical conditions 'very well by itself', whereas only 4.3% reported 'not very well'. A survey study of 2032 medical cannabis users found that 43.7% of the sample used cannabis to treat anxiety symptoms.[37] Of those using for anxiety, most respondents (92%) felt that cannabis improved their anxiety symptoms despite symptoms remaining moderately severe (mean GAD-7 score 9.8 ± 5.5). Higher anxiety severity was associated with greater amounts of cannabis used daily (P < 0.001) and nearly half (49%) reported replacing a drug prescribed to them by their physician with medical cannabis. Antidepressants, followed by opioids and benzodiazepines, were the most frequent drugs replaced by cannabis. Of note, 99% of this sample had used cannabis recreationally prior to their medicinal cannabis use.[37] A similar finding was reported from a sample of 2774 patients who use cannabis to treat various medical conditions: 58% substituted prescription medications with cannabis.[38] Specifically, 13.6% of patients substituted anxiolytic and benzodiazepine medications with medical cannabis, making these medications the second-most substituted drug class following narcotics/opioids (35.8%). In further support of these results, a survey of dispensary members (N = 1513) conducted by Piper et al.[39] revealed that 71.8% of respondents reduced their intake of antianxiety medications.

The Strainprint Cannabis Tracker is a smartphone application designed for medical cannabis users to track symptom changes as a function of cannabis use (dose and THC:CBD ratio can be tracked).[40] A sample of 5085 tracking sessions collected by the app, in which patients used cannabis to alleviate anxiety, were analyzed. Results were very positive, as users of the app reported significantly lower anxiety levels following cannabis use in 93.5% of sessions analyzed; only 2.1% experienced exacerbated symptoms, whereas 4.4% experienced no symptom change. With regards to THC:CBD ratio, patients perceived the largest stress reductions from high CBD cannabis products.[40]

Only one survey has investigated the long-term effects of cannabis on anxiety in a 3-year longitudinal survey of cannabis use in patients with a primary anxiety disorder diagnosis (N = 3723).[41] Between-group measures of remission rates and other mental health measures were compared among cannabis users, individuals with cannabis use disorder (CUD), and nonusers. Remission rates from anxiety disorders were higher among cannabis nonusers (66.0%) compared to cannabis users (52.8%), and were lowest among individuals with CUD (46.8%), however these differences were not statistically significant in adjusted models. Notably, 43% of those who reported long-term cannabis use qualified for a CUD diagnosis. Contrary to the majority of surveys reviewed, these results suggest that long-term cannabis use neither harms nor improves the course of anxiety disorders, but may increase risk of disordered use.[41]

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