A new scientific report has indicated that smoking weed is indeed detrimental to one’s intelligence levels.
According to a report by the Daily Mail, using the drug once a week for six months can knock off two IQ points and could have “significant effects” on one’s verbal skills.
Teens who smoke weed at least once a week for six months can lose up to two IQ points as they get older and find it harder to problem solve, a new study has revealed.
The Royal College of Surgeons in Ireland (RCSI) studied 808 teens who used cannabis at least weekly for at least six months and 5,038 who did not use the drug.
They discovered that regular weed users suffer a decline of two IQ points over time compared to those who did not use cannabis during their teen years.
Further analysis showed that verbal IQ, linked to understanding concepts, abstract reasoning, and memory, declines by three points among those who get high.
“Loss of IQ points early in life could have significant effects on performance in school and college and later employment prospects,” said senior author Mary Cannon.
Cannabis is the most frequently used illicit substance worldwide, with young people the most common users, according to the team behind this new research.
MRI scans taken as part of the study also revealed that those who smoked weed, even minimal incidental use while a teenager, showed reduced evidence of reduced grey matter in the brain.
A further study by Dr. Emmet Power said there was a clear association between frequent or dependent cannabis use and IQ change.
“This corresponds to a 1.98-point decline in IQ,” Dr Power said of the results.
“We found that young people who use cannabis frequently or dependently by age 18 have declined in IQ at follow up and this may be due to a decline in verbal IQ.”
“All studies showed point estimates of IQ decline,” Power added.
The two-point decline in IQ is “not clinically significant” and is unlikely to completely explain a range of psychologically susceptible to harm during this period.
“Cannabis use during youth is of great concern as the developing brain may be particularly susceptible to harm during this period,” Dr. Powers added.
The report further adds that this small drop in IQ points could lead to significant effects on performance in school, college and life generally which could then result in limited employment.
The findings were also published in a prominent medical journal, psychological medicine.
