Morin JFG, et al. - Researchers investigated how year-to-year changes in substance use influences cognitive development by using a developmentally sensitive design. They annually assessed a population-based sample of 3,826 seventh-graders from 31 schools—which consisted of 5% of all students entering high school in 2012 and 2013 in the Greater Montreal region—for 4 years on alcohol and cannabis use, recall memory, perceptual reasoning, inhibition, and working memory via school-based computerized assessments. Outcomes revealed common vulnerability effects for cannabis and alcohol on all domains. Lagged (neurotoxic) effects on inhibitory control and working memory and concurrent effects on delayed memory recall and perceptual reasoning (with some evidence of developmental sensitivity) were evident in correlation with cannabis use, but not with alcohol consumption. Irrespective of alcohol effects, cannabis effects were evident.