A recent study published by the American Journal of Epidemiology posits that smoking medical marijuana appeared to improve 'cognitive functioning' among middle aged men that participated in the study.
After looking at almost 9,000 men who used drugs, mostly marijuana, when they were 42, and then again when they turned 50, the study concluded that:
"A positive association was observed between ever (past or current) illicit drug use and cognitive functioning."
The same study concludes that:
"At the population level, it does not appear that current illicit drug use is associated with impaired cognitive functioning in early middle age."
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