A longitudinal randomized controlled trial in Canada revealed that concurrent and lasting effects of adolescent cannabis use can be observed on important cognitive function and appear to be more pronounced than those observed for alcohol. The study included a population-based sample of 3,826 seventh-grade students from 31 schools consisting of 5% of all students entering high school in 2012 and 2013 in the region. Cognition and substances use were assessed annually for 4 years. Common vulnerability effects were detected for cannabis and alcohol on all domains. Cannabis use, but not alcohol consumption, showed lagged (neurotoxic) effects on inhibitory control (a risk factor for other addictive behaviors) and working memory and concurrent effects on delayed memory recall and perceptual reasoning (with some evidence of developmental sensitivity). The findings suggest that the cognitive impairments of cannabis use may be causal. Source: https://ajp.psychiatryonline.org/
