Abstaining from pot improves memory in young users: study

BOSTON — Adolescents and young adults who regularly use cannabis but stop for 30 days have better memory and an improved ability to learn compared to peers who continue to smoke, vape or ingest pot, a study has found.

The study by researchers at Massachusetts General Hospital focused on two broad areas of cognitive function — attention and memory — in a group of 16to 25-year-olds who were regular users of cannabis, indulging at least once a week.

Roughly two-thirds of the 88 subjects were randomly assigned to abstain from weed for 30 days, while the remainder continued routine use. Researchers completed regular assessments of thinking and memory of participants during the 2015-16 study period.

Frequent urine tests were given to verify those in the no cannabis group had stayed away from the drug. Almost 90 per cent met the criteria for 30 days of continuous abstinence.

“Our findings provide two pieces of convincing evidence,” said lead author Randi Schuster, director of neuropsychology at the Center for Addiction Medicine at the Boston hospital.

“The first is that adolescents learn better when they are not using cannabis,” she said. “The second — which is the good news part of the story — is that at least some of the deficits associated with cannabis use are not permanent and actually improve pretty quickly after cannabis use stops.”

That improvement occurred largely during the first week of abstinence, say the authors, whose research was published Tuesday in the Journal of Clinical Psychiatry.

However, the study found no difference in attention — the ability to remain focused on a visual task, for instance — between the two groups by the end of 30 days.

Schuster said there are still a lot of questions to be studied.