Lifetime cannabis use is not associated with cognitive decline, according to longitudinal data published in the Journal Brain and Behavior. Investigators assessed the relationship between cannabis use and age-related cognitive decline in a cohort of 5,162 men. Subjects’ IQs were assessed during early adulthood (mean age: 22) and then again in late midlife (mean age: 62).
Researchers determined that participants with a history of cannabis use experienced “significantly less cognitive decline” over their lifetimes than did non-users. Among cannabis consumers, neither age of initiation nor frequency of use was associated with negative effects on cognition. Notably, cannabis users exhibited statistically significantly less cognitive decline compared to nonusers and the association remained significant when controlling for potential confounders. In the fully adjusted model, cannabis use was associated with 1.3 IQ points less cognitive decline than the decline observed in the reference group
The study’s authors concluded: “These findings align with most existing studies, suggesting no association between cannabis use and greater cognitive decline. Among cannabis users, no significant associations with age-related cognitive decline could be demonstrated for age of initiation of cannabis use. Years of frequent cannabis use were generally associated with no significant difference in cognitive decline when compared with no frequent use.”
