Cannabis for Depression and Anxiety: Little Benefit, Higher Risk of Cannabis Use Disorder

The hype surrounding the medical benefits of marijuana is of great concern. First, many individuals, including those with significant symptoms, do not get any relief with medical marijuana.  Even worse is that they may choose marijuana over other proven and efficacious treatments.  Furthermore, a study published by Jodi Gilman, PhD and her colleagues from the Center for Addiction Medicine at Mass General, indicates that procuring a medical marijuana card may also increase vulnerability to cannabis use disorder.

Specifically, the researchers looked at the effect of obtaining a medical marijuana card on cannabis use disorder (CUD) symptoms in adults presenting with chronic pain, insomnia, anxiety or depressive symptoms.  This single-blind randomized, controlled trial was conducted in the Greater Boston area between July 1, 2017 and July 31, 2020.  Participants (18 to 65 years) were randomized into two groups.  The first group received a medical marijuana card immediately (n = 105); the other group (n = 81) was asked to wait for 12 weeks before obtaining a card.  

Participants completed in-person visits at baseline and at weeks 2, 4, and 12 and a telephone visit at week 8 for an assessment of adverse events.  CUD symptoms were assessed by investigators using the CUD Checklist for the Diagnostic and Statistical Manual of Mental Disorders (Fifth Edition).  

Little Benefit, Higher Risk of Cannabis Use Disorder

The current study observed that in adults (mean age 37.2 years; 65.6% women) with pain, insomnia, depression, or anxiety, obtaining a medical marijuana card and using cannabis products from a dispensary increased the risk for developing CUD without significantly improving symptoms (other than sleep). The risk of developing CUD was nearly threefold higher in those who received a medical marijuana card immediately after the first visit compared to those in the delayed group.  Symptoms consistent with CUD developed quickly; the participants were followed only for 12 weeks and reported CUD symptoms, most commonly higher tolerance and continued use despite the recurrent physical or psychological problems caused or exacerbated by cannabis.  Longer follow-up is needed to determine whether individuals using marijuana for medical reasons face the same risk for CUD as recreational users; however, this study suggests that using marijuana for a medical reason may not protect the user from developing CUD.  

Depressive symptoms and anxiety are common complaints among individuals seeking medical marijuana.  Of particular concern is the finding in this study that those seeking medical marijuana for the treatment of anxiety and depressive symptoms were the most likely to develop CUD symptoms after acquiring the card.  Furthermore, they reported no benefit with regard to anxiety or depressive symptoms.  This finding is consistent with several earlier studies and suggests that a medical marijuana card may pose a high risk or may even be contraindicated for people with affective disorders.

Study raises questions about risks of using medical marijuana for mood and anxiety disorders (CNN)