Dr. Meier will present the results of a longitudinal study, recently published in the American Journal of Psychiatry, characterizing the cognitive functioning and brain integrity of long-term cannabis users in midlife. Case-control studies have shown that cannabis users exhibit subtle cognitive deficits and structural brain differences. However, most of these studies are of adolescents and young adults. It is unclear if the subtle cognitive and brain differences observed in young cannabis users are larger in midlife and older adult cannabis users with longer histories of use. This represents a significant gap in the literature because the prevalence of cannabis use is increasing rapidly among midlife and older adults, and cognitive reserves in midlife critically shape later-life dementia risk. Results from this population-representative longitudinal study of individuals followed to midlife show that long-term cannabis users exhibit midlife cognitive deficits and comprised brain integrity, with cognitive deficits comparable in magnitude to deficits among midlife individuals who go on to develop later-life dementia. Findings highlight the need to devote resources to midlife interventions for long-term cannabis users.