Emerson Rensink | The Anti-Media
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A recent study published by the University of Minnesota indicates that, in some areas, adolescent-onset marijuana use appears to improve cognitive function.
The study, published March 12, looked at 70 college-age adults. One group consisted of individuals who began smoking marijuana before the age of 17. The control group contained non-users. Image credit: youtube.com
In most areas of testing, the results were comparable. However, the group of marijuana users separated themselves from the non-users in tests that examined verbal fluency and processing speed, scoring relatively higher.
In a few areas of testing, the marijuana users scored slightly lower than their non-using counterparts. Those areas included verbal memory, spatial working memory, spatial planning and motivated decision making.
What’s remarkable about this study is its challenge to the assertion that marijuana use exclusively hampers brain development on teens and young adults. Although marijuana users scored lower on certain tests, their higher marks on other areas of testing appear to fly in the face of the long-held notion that marijuana is solely harmful on mental development.
In a 2012 study by Duke University, researchers came to the conclusion that marijuana use doesn’t stunt but actually decreases brain development in those who begin using during adolescence. In a longitudinal study, their research showed that marijuana users lost eight IQ points on average, whereas non-users maintained the same IQ level until midlife.
Some peer researchers challenged the study, positing that other correlations could account for the decrease in IQ among the sample of marijuana users.
One paper from Oxford University stated that socioeconomic status could account for disparity in IQ levels.
“The association [of marijuana use to declining IQ] is given a causal interpretation by the authors [of the Duke study], but existing research suggests an alternative confounding model based on time-varying effects of socioeconomic status on IQ… The causal effects estimated in [the Duke study] are likely to be overestimates, and… the true effect could be zero.”
Another researcher from the University of Sterling wrote a paper titled “Personality may explain the association between cannabis use and neuropsychological impairment.” In his abstract, the author states, “important omitted ‘third’ variables, such as stable individual differences in personality traits, could potentially cause both drug use and changes in intelligence.”
It should be noted that in the University of Minnesota’s study, it was found that the 18 to 20 year-olds examined in both groups had comparable IQ levels and that no detectable decline in intelligence had occurred for those who began using marijuana before the age of 17.
If nothing else, this recent study shows that more research is needed to determine the effect of marijuana use on developing brains, whether the effects are solely negative, and what exactly marijuana does to mental development.
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Emerson Rensink writes about social justice, activism and civil liberties. He’s been interviewed by alternative journalist pioneers such as Ben Swann and Dan Dicks for his work as an international co-organizer and media facilitator for the March Against Monsanto in 2013 and for exposing GOP corruption as a Ron Paul delegate in 2012. His work has appeared on WeAreChange.org, the Reason.com blog, PunkRockLibertarians.com and more.
Follow Emerson on Twitter: @emersonrensink