Marijuana use may cause cognitive impairment even when not still high

(NBC News) — Scott Isbell had been smoking weed since he was 17. By the time he turned 19, he was having difficulty setting goals and meeting deadlines at college. His grades had dropped from A’s to B’s and he was losing friends. Still, none of it seemed important enough to give up marijuana — until he started theater class.

“The class involved acting and memorizing things and I couldn’t remember anything,” said Isbell, now 27, and a communications expert and TV producer living in Concord, Massachusetts. “It was embarrassing. I felt like I was always playing catch up. My brain was stalled.”

Isbell sought help from the adolescent addiction program at Boston Children’s Hospital where doctors and therapists helped him cut back his cannabis use.

A recent analysis of previous research on the impact of cannabis on young’s people’s cognition found that many of the known learning and memory difficulties — such as slowed processing speed, and difficulties in focusing — could linger for weeks. Verbal learning, retention and recall were especially affected for longer periods when the person was no longer high, researchers from the University of Montreal found.

Read the full story on NBCNews.com.