Cannabusters myth #6: Smoking weed causes long-term cognitive damage

Oct 11 2018, 6:01 pm

Every day, in every way, cannabis legalization in Canada is getting closer. But despite all the hype, noise, and publicity, there seem to be recurring cannabis myths flying around that just won’t quit.

With six days to go until federal legalization, Grow’s daily Cannabusters series tackles common myths by cutting through the stigma and sensationalism to bring you the facts about cannabis.

Myth: Smoking weed causes long-term cognitive damage.

Fact: Consumers may experience some cognitive impairment while intoxicated, but those effects are not long-lasting.

Perhaps one of the biggest and most perpetuated cannabis myths is that consumption leads to long-term cognitive damage.

The stigmatized stoner stereotype is steeped in this myth, particularly for young consumers, leading to strong messages of “just say no.”

While cannabis is not without its harms, and can certainly lead to short-term impairment, evidence suggests that these effects dissipate after a short period of abstinence.

A meta-analysis published earlier this year in JAMA Psychiatry reviewed 69 studies that documented the implications of frequent cannabis use in adolescents and young adults.

A comparison of frequent-to-heavy users and their minimal-user counterparts showed only a small difference in cognitive function across a variety of tests which “may be of questionable clinical importance for most individuals.”

Furthermore, the differences were no longer significant after a 72-hour period of abstinence.

Outcomes related to psychosis were not examined, and it is advisable to exercise caution when consuming cannabis if you have a personal or family history with certain mental health disorders.

A separate study that examined the effects of cannabis and alcohol use in adolescents and adults found no impact on grey or white matter after 30 or more days of cannabis use. Alcohol use over the same time period was linked with a widespread reduction in both grey matter volume and white matter integrity in adults.

A 2011 study examined that looked at the relationship between the changes in cannabis use and cognitive performance over eight years suggests that even among heavy consumers, a period of abstinence was associated with “an improvement in capacity for recall of information that has just been learned.”

As we move towards and through legalization, continued research will help identify the positive, negative, and long-term effects of cannabis consumption. The evidence we have so far suggests that acute effects wear off after a period of abstinence, so maybe save your session ’til after exams.

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Jessica BrownJessica Brown

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