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Study breakdown

Medical cannabis dispensary users had high rates of mental illness when properly assessed

Cross SectionalModerate evidence
The takeaway

When 100 medical cannabis dispensary users were assessed with structured clinical interviews, lifetime mental illness prevalence was high, with particularly elevated rates of anxiety disorders and substance abuse/dependence.

Medical cannabis dispensary operators, mental health clinicians, and medical cannabis patients.

High anxiety disorder and substance abuse rates

What the researchers found

Using the MINI structured clinical interview, lifetime prevalence of mental illness was high. Current psychiatric disorder rates were low for mood disorders but high for anxiety disorders and substance abuse/dependence. Cannabis use patterns differed between psychiatric conditions. Many subjects endorsed psychological symptoms on standardized measures (stress, fatigue, sleep disturbance, depression, somatic symptoms, pain).

Why it matters

Most studies of dispensary users rely on self-report checklists. Using validated clinical instruments provides a more rigorous picture of mental health in this population.

The numbers in context

100 medical cannabis users. Structured MINI interview administered to all. Multiple standardized questionnaires completed. High lifetime mental illness prevalence. Low current mood disorder rates. High anxiety and substance disorder rates.

How the study worked

Cross-sectional study of 100 medical cannabis users recruited from a community dispensary. All completed the MINI structured clinical interview plus standardized questionnaires (Perceived Stress Scale-10, PROMIS Fatigue and Sleep scales, Beck Depression Inventory, PHQ-15, Brief Pain Inventory).

What this study cannot tell us

Cross-sectional design. Single dispensary. No control group. Cannot determine causation. Selection bias (dispensary users who agreed to participate). Sample may not represent all medical cannabis users.

How to read the evidence

Rigorous clinical assessment instruments, but cross-sectional single-site design without a control group.

When this study was published

2019 study.

The bigger picture

Whether cannabis use contributes to mental health problems or people with mental health problems are drawn to cannabis cannot be determined from this design, but the high co-occurrence is clinically important either way.

Questions still open

  • Are dispensary users getting appropriate mental health care alongside their cannabis use? Should dispensaries screen for psychiatric conditions?

Common questions

Do medical cannabis users have mental health problems?
In this study of 100 dispensary users assessed with clinical interviews, lifetime mental illness rates were high, particularly for anxiety disorders and substance abuse/dependence. Whether cannabis contributed to or resulted from these conditions is unknown.
How was mental health assessed in this study?
Unlike most dispensary studies that use self-report checklists, this study used the MINI structured clinical interview (the same tool used in clinical drug trials) plus multiple validated questionnaires.

Read the original research

Characterization of mental health in cannabis dispensary users, using structured clinical interviews and standardized assessment instruments.

BMC psychiatry, 19(1), 335

Citation

Yau, Jade C; Yu, Shu Min; Panenka, William J; Pearce, Hadley; Gicas, Kristina M; Procyshyn, Ric M; MacCallum, Caroline; Honer, William G; Barr, Alasdair M. (2019). Characterization of mental health in cannabis dispensary users, using structured clinical interviews and standardized assessment instruments.. BMC psychiatry, 19(1), 335. https://doi.org/10.1186/s12888-019-2324-z

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