A small, 5-year French study of cannabis-related reports of adverse events found an association with cardiovascular complications. The death rate was 25.6% and the average age was 34 years old. This is difficult to study because of the extreme variation in THC concentrations, the frequent use of other drugs, and the lack of strong control groups. More research is needed to determine if this association is causal.
PositiveTip: Though widely believed that cannabis use is harmless, evidence suggests it may be very risky.