Teens Who Use Marijuana Show Decline in Intelligence Later On
Jim Liebelt Jim Liebelt's Blog
- 2021 Feb 04
*The following is excerpted from an online article posted on Study Finds.
While nations argue over how intelligent it is to legalize marijuana, a new study finds the drug may literally be impacting the intelligence of young users. Researchers from the Royal College of Surgeons in Ireland (RCSI) say frequent use of cannabis during adolescence can lead to having a lower IQ as an adult.
Researchers have discovered that regular pot smokers suffer a decline of two IQ points over time compared to those who did not use cannabis as an adolescent. Further analysis revealed verbal IQ, which refers to understanding concepts, abstract reasoning, and working memory, declines by three points.
While that may not sound significant, study authors say even minimal incidental contact with marijuana can result in morphological brain volume changes. An analysis of MRI studies discovered those who smoked weed showed evidence of reduced grey matter in the brain.
“Previous research tells us that young people who use cannabis frequently have worse outcomes in life than their peers and are at increased risk for serious mental illnesses like schizophrenia,” says senior author Professor Mary Cannon in a university release. “Loss of IQ points early in life could have significant effects on performance in school and college and later employment prospects.”
The RCSI team studied 808 young people who used cannabis at least weekly for a minimum of six months. They also examined 5,308 young people who did not use the drug.
The results reveal significant differences in terms of IQ between the two groups. Researchers say, among frequent or dependent cannabis users, overall IQ dropped by 1.98 points. When examining the impact on verbal IQ using four available studies, the team discovered a 2.94-point drop in these scores.
“Cannabis use during youth is of great concern as the developing brain may be particularly susceptible to harm during this period. The findings of this study help us to further understand this important public health issue,” explains study first author Dr. Emmet Power.
Source: Study Finds