Effect of Medical Cannabis for Pain, Insomnia, Anxiety and Depressive Symptoms

Jodi Gilman, PhD

A team of investigators, led by Jodi Gilman, PhD, Department of Psychiatry, Massachusetts General Hospital, stated that there’s not much known on the risks and benefits of obtaining a medical marijuana card. The investigators looked at cannabis use disorder (CUD) symptoms among adults who attained a card in order to address chronic pain, insomnia, or anxiety and depressive symptoms.

Ultimately, the findings of the study suggested a need to further examine the benefits that adults with a medical marijuana card experience when dealing with insomnia symptoms or those related to affective disorders. The risk of cannabis use disorder also needs to be more thoroughly investigated, particularly among adults with anxiety or depressive symptoms.

According to the study, adults who immediately acquired a card had an increased incidence and severity of cannabis use disorder. No significant improvements were shown regarding symptom relief in any of the disorders focused on, except for the self-reported ratings of insomnia symptoms.

Obtaining a Medical Marijuana Card

The primary outcomes of the pragmatic, single-site, single-blind randomized clinical trial were changes in cannabis use disorder symptoms, anxiety and depressive symptoms, pain severity, and insomnia symptoms. Adults between 18-65 years of age with concern in one or more of these areas were included in the trial.

When estimating the odds ratio (OR) for CUD diagnosis, a logistic regression model was used; for the symptom scores, linear models were used for continuous outcomes in order to estimate the mean difference (MD).

The trial was conducted in the Greater Boston area from July 2017-July 2020. After the 186 adults were randomized 2:1 to either the immediate card acquisition (n=105) group or the delayed card acquisition group (n=81), they were stratified by primary concern, age, and sex.

While the immediate acquisition group received a card directly following randomization, the delayed group was asked to wait 12 weeks. Individuals were encouraged to use their own discretion when choosing products from a dispensary, the dose, and frequency of use. They were also permitted to continue their usual medical and psychiatric care.

Risks & Benefits of Cannabis Use with a Card

When comparing the two groups, investigators found that the immediate card group had more cannabis use disorder symptoms (MD, 0.28; 95% CI, 0.15-0.40; P < .001); fewer self-rated insomnia symptoms (MD, –2.90; 95% CI, –4.31 to –1.51; P < .001); and reported no significant changes in pain severity or anxiety or depressive symptoms. The incidence of CUD was also higher in immediate card group during the intervention (17.1% [n = 18]) compared with the delayed group (8.6% [n = 7]; adjusted odds ratio,2.88; 95% CI, 1.17-7.07; P = .02).

The incidence of CUD was particularly higher among adults who identified anxiety or depressive symptoms as their primary concern. Investigators noted that most cases of CUD onset were mild, with 2-4 symptoms, but they developed over a short, 12-week initial exposure.

In terms of recreational cannabis use, epidemiologic surveys have shown that 3 in 10 adults who use cannabis develop CUD. However, it’s unclear how the rate of CUD presents among adults with a medical marijuana card compared with those who use recreationally.

“Thus, further research is warranted with a longer follow-up of people who obtain a card to better understand CUD risk in this group,” investigators wrote. “This trial showed that CUD can develop at a fast rate within the first 12 weeks of medical marijuana card ownership, suggesting that those with a card may develop CUD at a similar rate as those who use cannabis recreationally and that the motive for use (eg, medical) may not be protective.”

The study “Effect of Medical Marijuana Card Ownership on Pain, Insomnia, and Affective Disorder Symptoms in Adults” is published in JAMA Network Open.