A naturalistic examination of the perceived effects of cannabis on negative affect

BACKGROUND: tetrahydrocannabinol (THC) and cannabidiol (CBD). METHOD: (which provides medical cannabis users a means of tracking changes in symptoms as a function of different doses and chemotypes of cannabis) were analyzed using multilevel modeling. In total, 11,953 tracked sessions were analyzed (3,151 for depression, 5,085 for anxiety, and 3,717 for stress). RESULTS: Medical cannabis users perceived a 50% reduction in depression and a 58% reduction in anxiety and stress following cannabis use. Two puffs were sufficient to reduce ratings of depression and anxiety, while 10+ puffs produced the greatest perceived reductions in stress. High CBD (>9.5%)/low THC (11%)/high THC (>26.5%) cannabis produced the largest perceived changes in stress. No changes in the perceived efficacy of cannabis were detected across time. However, baseline symptoms of depression (but not anxiety or stress) appeared to be exacerbated across time/tracked sessions. LIMITATIONS: The primary limitations are the self-selected nature of the sample and the inability to control for expectancy effects. CONCLUSIONS: Cannabis reduces perceived symptoms of negative affect in the short-term, but continued use may exacerbate baseline symptoms of depression over time.