Most of the damage is reversible, if you stay off long enough STUDY: Ricci V et al, Am J Addict 2026 STUDY TYPE: Systematic review FUNDING: Independent Background Does heavy cannabis use permanently changed the brain? This review pulls together 26 studies to answer that, tracking recovery across neuroimaging, cognitive testing, and biomarkers after cessation. The Study 26 studies, 2,816 participants: mostly cross-sectional and longitudinal designs, plus three randomized trials.