Study register · detailProspektive Kohortenstudie · Depression Risk · 2016
Cannabis use, depression and anxiety: A 3-year prospective population-based study
Danielsson et al.·Journal of Affective DisordersImpact 4.3
No benefit demonstratedGRADELow101 citations
Samplen = 8.598 Pat.
Duration3-year follow-up
ControlNo cannabis use
EndpointRelative risk
Blindingn.a.
DesignProspektive Kohortenstudie
”Key finding
After full confounder adjustment there was no significant longitudinal association between cannabis use and depression or anxiety disorders in either direction.
Summary
n=8.598 Swedish adults (20–64 years), 3-year follow-up; cannabis use at baseline → depression: RR=1,22 [95% CI 1,06–1,42] unadjusted, no longer significant after full adjustment (alcohol, drugs, education, family tension) RR=0,99 [95% CI 0,82–1,17]; → anxiety: RR=1,38 [95% CI 1,26–1,50] unadjusted, adjusted RR=1,09 [95% CI 0,98–1,20] (NS). No longitudinal association between cannabis use and new onset depression or anxiety after full confounder control.
P
PopulationSwedish men and women aged 20–64 years from the general population, n=8.598
I
InterventionCannabis use (self-report at baseline)
C
ControlNo cannabis use
O
OutcomeAfter full confounder adjustment no significant associations: RR=0,99 [95%-CI 0,82–1,17] for depression and RR=1,09 [95%-CI 0,98–1,20] for anxiety disorders at follow-up; conversely no significant effect of depression/anxiety on later cannabis use after adjustment for other drug use
Confidence in the evidence
Very lowLowModerateHigh
Low
The second of four GRADE levels, the effect estimate is of limited reliability.
<h4>Background</h4>Whether or not cannabis use may increase the risk for depression and/or anxiety is not clear. For one thing, it has not been possible to draw a definitive conclusion regarding the direction of causality, i.e. whether cannabis use increases the risk for depression/anxiety or vice versa. This study aimed at examining possible associations between cannabis use, depression and anxiety, using all three measures as both exposure and outcome.<h4>Methods</h4>Data were obtained from a longitudinal cohort study comprising 8598 Swedish men and women, aged 20-64, with a three-year-follow-up.<h4>Results</h4>Adjusted for sex and age, cannabis use at baseline was associated with an increased relative risk (RR) for depression and anxiety at follow-up, with RR=1.22 [1.06-1.42 Cl 95%] for depression and RR=1.38 [1.26-1.50 Cl 95%] for anxiety. Adjusted for all confounders (alcohol and illicit drug use, education, family tension, place of upbringing), the associations were no longer statistically significant; RR=0.99 [0.82-1.17 Cl 95%] for depression and RR=1.09 [0.98-1.20 Cl 95%] for anxiety. Age-adjusted, reporting depression or anxiety at baseline increased the risk of cannabis onset at follow-up three years later; RR=1.62 [1.28-2.03 CI 95%] and RR=1.63 [1.28-2.08 CI 95%] respectively. However, adjusted for other illicit drug use the associations were no longer statistically significant.<h4>Limitations</h4>Lack of information on frequency of cannabis use and of age of initiation of use.<h4>Conclusions</h4>We found no longitudinal associations between cannabis use and incidence of depression/anxiety, or between depression/anxiety and later cannabis use onset.