Cognitive, physical, and mental health outcomes between long-term cannabis and tobacco users

Introduction: Cannabis intoxication adversely affects health, yet persistent effects following short-term abstinencein long-term cannabis users are unclear. This matched-subjects, cross-sectional study compared healthoutcomes of long-term cannabis and long-term tobacco-only users, relative to population norms.Methods: Nineteen long-term (mean 32.3 years of use, mean age 55.7 years), abstinent (mean 15 h) cannabisusers and 16 long-term tobacco users (mean 37.1 years of use, mean age 52.9 years), matched for age, educationalattainment, and lifetime tobacco consumption, were compared on measures of learning and memory,response inhibition, information-processing, sustained attention, executive control, and mental and physicalhealth.Results: Cannabis users exhibited poorer overall learning and delayed recall and greater interference and forgettingthan tobacco users, and exhibited poorer recall than norms. Inhibition and executive control were similarbetween groups, but cannabis users had slower reaction times during information processing and sustainedattention tasks. Cannabis users had superior health satisfaction and psychological, somatic, and general healththan tobacco users and had similar mental and physical health to norms whilst tobacco users had greater stress,role limitations from emotional problems, and poorer health satisfaction.Conclusions: Long-term cannabis users may exhibit deficits in some cognitive domains despite short-term abstinenceand may therefore benefit from interventions to improve cognitive performance. Tobacco alone maycontribute to adverse mental and physical health outcomes, which requires appropriate control in future studies