Teenagers who began using cannabis improved more slowly in memory, attention, language, and processing speed than peers who did not, according to an analysis of 11,036 children followed from ages 9 and 10 through ages 16 and 17.
The pattern the researchers describe is specific. In some cases, these teens performed as well as, or slightly better than, other children when they were younger. As they got older and started using cannabis, their progress leveled off while their peers continued improving.
