Cannabis and suicide: longitudinal study.
BACKGROUND
Some studies suggest that cannabis use is associated with suicidal ideation, but no detailed longitudinal study has examined suicide as an outcome.


OBJECTIVE
To examine the association between cannabis use and completed suicide.


METHODS
A longitudinal study investigated 50 087 men conscripted for Swedish military service, with cannabis use measured non-anonymously at conscription. Suicides during 33 years of follow-up were identified by linkage with the National Cause of Death Register.


RESULTS
There were 600 (1.2% of cohort) suicides or deaths from undetermined causes. Cannabis use was associated with an increased risk of suicide (crude OR for 'ever use' 1.62, 95% CI 1.28-2.07), but this association was eliminated after adjustment for confounding (adjusted OR = 0.88, 95% CI 0.65-1.20).


CONCLUSIONS
Although there was a strong association between cannabis use and suicide, this was explained by markers of psychological and behavioural problems. These results suggest that cannabis use is unlikely to have a strong effect on risk of completed suicide, either directly or as a consequence of mental health problems secondary to its use.
Price
Ceri
C
Department of Psychological Medicine, School of Medicine, Cardiff University, Heath Park, Cardiff CF14 4XN, UK.
Hemmingsson
Tomas
T
Lewis
Glyn
G
Zammit
Stanley
S
Allebeck
Peter
P
D000293:Adolescent; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D002189:Marijuana Abuse / Q000401:mortality / Q000523:psychology*; D008889:Military Personnel; D016017:Odds Ratio; D012307:Risk Factors; D013405:Suicide / Q000523:psychology* / Q000706:statistics & numerical data; D013548:Sweden / Q000453:epidemiology; D055815:Young Adult