While any substance use by teens is not a good idea, new studies show that it isn’t cannabis use that is giving teens lower IQs. Despite all the stereotypes of lazy and stupid, vacant-eyed ‘stoners’, it turns out that the biggest factors in lower IQ are tobacco and alcohol.
Big study reveals truth
Recently published in the Journal of Psychopharmacology, and conducted by the Avon Longitudinal Study of Parents and Children Cohort (ALSPAC), the study found that cannabis use in teens has no significant detrimental effect on IQ when compared with similar teens who had never reported trying it. With a huge pool of over 2,200 subjects, tested at 8 years old and again at 15, it is one of the largest and most accurate studies to date.
A previous study, conducted by PNAS and released in 2012 claimed that persistent cannabis use in teens had a negative effect on IQ compared to teens who did not use, especially when started young.