Study register · detailKohortenstudie · Depression · 2020
Changes in patient health questionnaire (PHQ-9) scores in adults with medical authorization for cannabis.
Round et al.·BMC public healthImpact 4.1
No benefit demonstratedGRADELow15 citations
Samplen = 5.103 Pat.
Durationup to 3,2 years
EndpointPHQ-9
Blindingn.a.
DesignKohortenstudie
Cannabinoidvollspektrum
”Key finding
Medical cannabis led to a statistically significant but clinically non-meaningful reduction in PHQ-9 scores of on average 0,20 points; 95,1% of patients showed no clinically relevant change.
Summary
Prospective cohort study in n=5.103 medically authorized cannabis patients (50% with depression at baseline), median follow-up 196 days (IQR 77-451). Mean PHQ-9 change -0,20 points (95% CI -0,26 to -0,14, p<0,0001); 95,1% without clinically relevant change, 3,4% improvement, 1,5% worsening. No clinically meaningful overall effect on depressive symptomatology.
P
PopulationAdults with medical cannabis authorization in Ontario and Alberta, Canada, n=5.103 (follow-up cohort from 37.338 patients), mean age 54 years, 46% male, 50% with baseline depression
I
InterventionMedically authorized cannabis (type, dose, route not specified)
O
OutcomeMean PHQ-9 change from baseline to follow-up: -0,20 (95% CI: -0,26 to -0,14, p<0,0001); 95,1% without clinically relevant change, 3,4% with improvement, 1,5% with worsening
Confidence in the evidence
Very lowLowModerateHigh
Low
The second of four GRADE levels, the effect estimate is of limited reliability.
Quality profile
Sample size★★★★★
Blinding—
Effect sizeNo benefit
Citations / year★★★★★
Authors
Round JM, Lee C, Hanlon JG, Hyshka E, Dyck JRB, Eurich DT
Background: Legal access to medical cannabis is increasing world-wide. Despite this, there is a lack of evidence surrounding its efficacy on mental health outcomes, particularly, on depression. This study assesses the effect of medical cannabis on Patient Health Questionnaire (PHQ-9) scores in adult patients between 2014 and 2019 in Ontario and Alberta, Canada.
Methods: An observational cohort study of medically authorized cannabis patients in Ontario and Alberta. Overall change in PHQ-9 scores from baseline to follow-up were evaluated (mean change) over a time period of up to 3.2 years.
Results: 37,338 patients from the cohort had an initial PHQ-9 score recorded with 5103 (13.7%) patients having follow-up PHQ-9 scores. The average age was 54 yrs. (SD 15.7), 46% male, 50% noted depression at baseline. The average PHQ-9 score at baseline was 10.5 (SD 6.9), following a median follow-up time of 196 days (IQR: 77-451) the average final PHQ-9 score was 10.3 (SD 6.8) with a mean change of - 0.20 (95% CI: - 0.26, - 0.14, p-value < 0.0001). Overall, 4855 (95.1%) had no clinically significant change in their PHQ-9 score following medical cannabis use while 172 (3.4%) reported improvement and 76 (1.5%) reported worsening of their depression symptoms.
Conclusions: Although the majority showed no clinically important changes in PHQ-9 scores, a number of patients showed improvement or deteriorations in PHQ-9 scores. Future studies should focus on the parallel use of screening questionnaires to control for PHQ-9 sensitivity and to explore potential factors that may have attributed to the improvement in scores pre- and post- 3-6 month time period.