The more teenagers delay smoking marijuana until they're older, the better it is for their brains, but there may be little ill effect if they start after age 17, says a new Université de Montréal study.
Adolescents who smoke pot as early as 14 do worse by 20 on some cognitive tests and drop out of school at a higher rate than non-smokers, confirms the study, published Dec. 29 in Development and Psychopathology, a Cambridge University Press journal.
http://nouvelles.umontreal.ca/en/article/2017/01/24/-d994f54a11/
