I would really like this question answered by a professional as it seems that most of the articles I read online are very heavily biased. Articles on marijuana related sites promote it and say its harmless and on the other hand there are a lot of sites that completely antagonize it.

A completely unbiased technical approach would be great as I truly don't know which articles to believe :)

(I'm especially interested in long-term cognitive effects)

  • What type of professional do you want to answer this question? A doctor or scientist that specializes in marijuana and it's side effects long term, or perhaps you would consider an elderly man that has smoked for many years to discuss on the topic from his perspective. In terms of "professional" with this topic, please give a more clear definition of what you mean credentials wise for a profession in this respect.
    – Facebook
    Sep 4, 2016 at 0:46

1 Answer 1


A recent literature review of the evidence regarding long term effects of cannabis (3 weeks or longer since last use) reported:

Cannabis appears to continue to exert impairing effects in executive functions even after 3 weeks of abstinence and beyond. While basic attentional and working memory abilities are largely restored, the most enduring and detectable deficits are seen in decision-making, concept formation and planning. Verbal fluency impairments are somewhat mixed at this stage. Similar to the residual effects of cannabis use, those studies with subjects having chronic, heavy cannabis use show the most enduring deficits.

The complete review is open access and available here:

Crean RD, Crane NA, Mason BJ. An Evidence Based Review of Acute and Long-Term Effects of Cannabis Use on Executive Cognitive Functions. Journal of addiction medicine. 2011;5(1):1-8. doi:10.1097/ADM.0b013e31820c23fa.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct.

Not the answer you're looking for? Browse other questions tagged or ask your own question.