Study data published in JAMA Network Open found no association between the acquisition of a medical marijuana card and improvement in pain, anxiety, or depressive symptoms. Further, possession of a medical marijuana card increased the risk for cannabis use disorder (CUD). However, self-rated insomnia symptoms appeared to improve following marijuana card ownership.

Despite its increasing commercialization for medical use, the clinical benefits of cannabis are poorly understand. To better explore the effects of medical marijuana, investigators conducted a pragmatic, single-site, single-blind randomized controlled trial in the Greater Boston area between 2017 and 2020.

Adults seeking medical marijuana for the treatment of pain, insomnia, anxiety, or depressive symptoms were randomized 2:1 to either the immediate card acquisition group or the delayed acquisition group. The immediate acquisition group was allowed to obtain a medical card immediately after baseline assessment; the delayed acquisition group was asked to wait 12 weeks. Randomization was stratified by baseline clinical concern, age, and sex.

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The primary outcomes were changes in CUD symptoms, anxiety and depressive symptoms, pain severity, and insomnia symptoms at weeks 2, 4, and 12. Linear regression models were used to estimate the mean difference (MD) in symptom scores over the 12-week trial. Logistic regression was used to estimate the odds ratio (OR) for CUD diagnosis.

The study cohort comprised 186 patients aged a mean of 37.2 ± 14.4 years, among whom 122 (65.6%) were women. A total of 105 were randomized to immediate acquisition and 81 were assigned to delayed acquisition.

Participants in the immediate card acquisition group reported a greater number of CUD symptoms at week 12 compared with the delayed acquisition group (MD, 0.28; 95% CI, 0.15-0.40; P <.001).  No substantial changes in pain severity or anxious or depressive symptoms were observed in the immediate acquisition group at 2, 4, or 12 weeks. However, the immediate acquisition group had fewer self-rated insomnia symptoms at week 12 compared with the delayed group (MD, -2.90; 95% CI, -4.31 to -1.51; P <.001).

Patients in the immediate acquisition arm were more likely to fit the criteria of a CUD diagnosis at week 12 compared with the delayed arm (OR, 2.88; 95% CI, 1.17-7.07; P =.02). Specifically, 17.1% of patients in the immediate acquisition group developed a CUD, compared with 8.6% in the delayed acquisition group. Risk of CUD was particularly elevated in patients with anxiety or depression.

Results from this randomized clinical trial suggest that medical marijuana does not substantially improve clinical pain, anxiety, or depressive symptoms, though it may offer help to those with insomnia. Additionally, medical marijuana card acquisition was associated with substantially greater odds of developing a use disorder. Study limitations include the lack of standardization across cannabis products and dosing, as well as the relatively small cohort size.

“Further investigation of the benefits of medical marijuana card ownership for insomnia and the risk of CUD are needed, particularly for individuals with anxiety or depressive symptoms,” investigators wrote.

Disclosure: Two study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures. 


Gilman JM, Schuster RM, Potter KW, et al. Effect of medical marijuana card ownership on pain, insomnia, and affective disorder symptoms in adults: a randomized clinical trial. JAMA Netw Open. 2022;5(3):e222106. doi:10.1001/jamanetworkopen

This article originally appeared on Psychiatry Advisor