Marijuana and Early Mortality

Swedish male military conscripts who had used pot 50 times or more before the age of 18 were 40% more likely than their abstemious peers to be dead by age 60. Legalize it if you want, but don't call it "safe." And, yeah, yeah, correlation can't prove causation, but correlational studies are how we know that tobacco isn't safe. You can't randomly assign some people to smoke a lot of dope and then others to serve as a control. There are underlying factors at work as to why some Swedish kids became potheads and others didn't AND there are underlying reasons why some people smoke cigarettes for 20 years and others don't.

American Journal of Psychiatry




Cannabis, Psychosis, and Mortality: A Cohort Study of 50,373 Swedish Men
                   

Edison Manrique-Garcia, M.D., Ph.D., Antonio Ponce de Leon, Ph.D., Christina Dalman, M.D., Ph.D., Sven Andréasson, M.D., Ph.D., Peter Allebeck, M.D., Ph.D.

Objective:

The authors assessed 1) the overall risk of death among cannabis users compared with nonusers and the extent to which psychosis affects excess mortality; 2) mortality among persons with psychotic disorders and the extent to which cannabis use affects excess mortality; and 3) the interaction effect of cannabis use and diagnosis of psychotic disorders on mortality.

Method:

This was a longitudinal study of 50,373 Swedish male military conscripts (ages 18–19) who were followed in the National Cause of Death Register up to around age 60. Cox proportional hazard modeling was used to assess risk of death in relation to baseline cannabis use and diagnosis of psychotic disorders.

Results:

Subjects with a baseline history of heavy cannabis use had a significantly higher risk of death (hazard ratio=1.4, 95% CI=1.1, 1.8) than those without such a history. The authors found an excess mortality among subjects with psychotic disorders, but the level did not differ between those with a history of cannabis use (ever users: hazard ratio=3.8, 95% CI=2.8, 5.0; heavy users: hazard ratio=3.8, 95% CI=2.6, 6.2) and those without such a history (hazard ratio=3.7, 95% CI=3.1, 44). No interaction was observed between cannabis use and diagnosis of psychotic disorders with regard to mortality.

Conclusions:

The results suggest that individuals with an early history of heavy use of cannabis are at a higher risk of death than those with a history of no use of cannabis. Although the authors adjusted for several confounders at baseline, the results should be interpreted with caution because of a lack of information on confounders in the period after conscription.