Does cannabis use affect IQ scores? That’s what a new study says

Does cannabis use, both medicinal and recreational, adversely affect cognitive function? As the number of studies looking at cannabis exposure and cognitive impairment with mixed findings increases, the topic becomes more controversial.

A 2001 study published in the journal Archives of General Psychiatry found that “ex-marijuana smokers showed no cognitive impairment,” as did a study published four years later in the journal Neurotoxicology and Teratology.

At the other end of the spectrum are studies that suggest the opposite. As a rule, such studies primarily focus on the long-term outcomes of those who started marijuana use earlier in life, comparing statistically significant changes in cognitive function in those who use cannabis and those who do not.

New research

One such example is a recent study that followed 1,037 New Zealanders aged 3 to 45 to determine the effect of marijuana on brain function.

The study, published in the American Journal of Psychiatry, found that those who used cannabis long-term and regularly did experience cognitive impairment.

In addition to a 5.5-point drop in IQ from infancy to midlife, the results confirmed some deficits in learning and processing speed compared to non-marijuana users.

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In addition, long-term cannabis users also developed memory and attention problems, the study found.

However, experts said more studies are needed to assess whether long-term marijuana users have an increased rate of dementia later in life.

This article originally appeared on Benzinga and has been republished with permission.