Previously reported risk factors associated with problematic cannabis include frequent use of high potency THC, male gender, younger age of cannabis initiation, adverse childhood experiences, and use of other illicit drugs.^8,9 Problematic cannabis use has been associated with a host of adverse outcomes including poorer work or social functioning, interference with productivity, withdrawal symptoms such as anxiety or fatigue, and worsening mental health.^7,13,19,20 This study assessed risk factors for problematic cannabis use and prevalence in a sample of cannabis dispensary users who self-endorsed the use of cannabis for medical purposes. Interestingly, the prevalence of problematic cannabis use was high within this sample (30%). Gender, current or past MDD episodes, and BDI score risk factors were not significantly associated with problematic cannabis use; however, the age of cannabis initiation and self-reported use for depression were statistically significant

The findings related to gender and depression indicate that risk profiles for problematic cannabis use may differ, in some aspects, for those consuming with purely recreational intent compared to a medical intent. For example, male gender has been associated with an increased risk of problematic cannabis use in the recreational literature.⁸ This risk for males is theorized in part to come from greater engagement in risk-taking behaviors compared to females.²¹ However, our data showed no significant difference in prevalence between genders, suggesting that medical intent of use, in which there is a common goal of symptom control, may negate this risk factor. Although the lack of difference between genders is just one example of divergence in findings between recreational and medical samples, it supports the notion that previously reported risk factors for problematic cannabis use should be re-examined within the context of medical use.

Clinical concerns about the association between mental health and problematic cannabis use exist within both recreational and medical cannabis-use contexts. Mental health disorders are often co-morbid with substance use disorders.²² The links between cannabis use and mental health are complex, and establishing directionality remains an ongoing challenge. Previous literature from both medical and recreational populations has identified depression as a risk factor for subsequent problematic use.²³ Consistent with this, individuals with problematic cannabis use currently reported using cannabis more frequently to relieve depressive symptoms. However, in our findings, neither validated mental health scale scores nor diagnoses of current or prior MDD were significantly associated with problematic cannabis use. Notably, however, 43% of individuals with problematic use were diagnosed with a past MDD episode, but only 3% met the criteria for a current disorder. Although preliminary, one possibility for this large difference is that cannabis has been helpful in controlling their depressive symptoms—however, this will clearly take substantial further research in this population to confirm. Cannabis has long been subject to conflicting findings as to whether it hinders or improves mental health. While the evidence is in no way conclusive, there are reported findings that cannabis may improve some symptoms of depressive disorders.²⁴ Intent of use and patient education on how to use cannabis with a safety-focused approach may be a key differentiating factor between mental health improvement or harm.

Finally, the high level of problematic cannabis use in this sample may point out important differences and risks between self-treating medical cannabis users and healthcare professional (HCP)-guided medical cannabis users. Although participants reported using cannabis for medical purposes, only 10% reported medical cannabis use was recommended by their doctor. A lack of guidance and education due to the self-taught nature of these individuals may have increased the risk of problematic use. In patients working with an HCP, as is seen with authorized medical cannabis users in Canada, continued monitoring and guidance from HCPs allow for intervention prior to problematic use. Therefore, to mitigate risk, individuals should be encouraged to seek HCP guidance when using cannabis medically. Additionally, HCPs should have open, non-judgmental conversations with their patients to assess if cannabis is being used medically. If it is, and the HCP is not comfortable with managing care, the patient should be referred to a clinician experienced in medical cannabis where they can receive proper education and guidance on how to meet their treatment goals. For all individuals who are using cannabis recreationally, that is, recreational only or medical intent + some recreational use, lower-risk approaches for recreational cannabis use, such as those outlined in Canada’s Lower-Risk Cannabis Use Guidelines, should be encouraged.²⁵

An equally important consideration when assessing the seemingly high rate of problematic use is the validity of measures for medical cannabis users. As with most scales, including the MINI-6, the assumed sample is a general population who are not using cannabis with medical intent. Medical patients use cannabis more frequently and chronically, which may lead them to be misclassified as higher risk due to additional scoring for frequency of use. There is currently a paucity of research investigating problematic cannabis use and mental health in medical cannabis users. In order to better classify risk within this population, it will be important to develop validated tools appropriate for these medical users. Moreover, evidence from this study supports that, within the medical population, there are important differences between those self-treating versus receiving guidance from an HCP. Therefore, risk factors likely differ between recreational, self-treating medical, and HCP-treated medical cannabis users; This should be considered in future research.

The modest sample size may have limited our statistical power and decreased the ability to make broad generalizations confidently. Although important findings were observed with the current sample size of 100 participants, future investigations will benefit from evaluating larger sample sizes. The self-report nature of measures may have also impacted the precision of results, as external verification of answers (such as from medical chart review) was beyond the scope of the study. Finally, though individuals reported using cannabis for medical purposes, few were supervised by an HCP. This may have led to some participants using in a manner more similar to recreational users. Evaluations on the differences between recreational, self-reported medical use and medical cannabis use under the guidance of an HCP should also be undertaken.