Yes, Marijuana Does Impair Memory
To the surprise of few, marijuana does impair learning and memory. According to the University Hospital Patras, this is particularly true for heavy users, people who have frequently used marijuana for at least five years.
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Meanwhile, NORML reports that Dutch researchers found quite the opposite.
Given the short mean time since last dosage (24 hours) of the Greek experiment, and the longer time of the Dutch experiment (one week), the different result is not surprising. Nor is which result gets the widespread press surprising. Truth is the first casualty of war.
The P values (~less than .001) reported by the Greek experiment, given the small sample size (64) also seem very small. It would be interesting to see their actual experimental design and analysis.
http://norml.org/index.cfm?Group_ID=6832
March 9, 2006 - Utrecht, Netherlands
Utrecht, the Netherlands: Frequent cannabis use is not associated with cognitive deficits in memory or attention, according to trial data published in the forthcoming issue of the journal Psychopharmacology.
Investigators at the Rudolf Magnus Institute of Neuroscience assessed brain function in "frequent but relatively moderate" cannabis users in the domains of working memory and selective attention using functional magnetic resonance imagining (fMRI).
"No evidence was found for long-term deficits in working memory and selective attention in frequent cannabis users after one week of abstinence" compared to non-using healthy controls, authors concluded. "Furthermore, cannabis users did not differ from controls in terms of overall patterns of brain activity in the regions involved in these cognitive functions."
Posted by: Anon | March 16, 2006 01:44 PM