ATLANTA (CBS Atlanta) - A new study has found that people who smoked marijuana during their rebellious teenage years may pay for it as adults.
According to a press release issued by the Surgeon General of the Public Health Service and posted on the website for the Centers for Disease Control and Prevention in Atlanta, the previously noted negative effects of chronic marijuana use include short-term memory loss, decreased sperm count in male users and impaired lung function.
But researchers at Duke University in Durham, N.C. have reportedly found another detrimental result – a marked decline of a user’s intelligence quotient, or IQ, as they aged.
According to a press release on the study posted on the school’s official website, over 1,000 New Zealand residents who started smoking marijuana before the age of 18 were polled by researchers.
An average IQ drop of 8 points was found in pot smokers between age 13 and age 38, after tests taken during those two years of life were compared, with persistent users especially effected. Researchers additionally found that quitting smoking did not help or halt these documented long-term effects.
“Marijuana is not harmless, particularly for adolescents,” lead researcher Madeline Meier, a post-doctoral researcher at Duke University, was quoted as saying.
A drop in IQ from 100 to 92 would signify dropping from the 50th percentile to the 29th, Meier noted in the press release.
“Somebody who loses 8 IQ points as an adolescent may be disadvantaged compared to their same-age peers for years to come,” she added.
The study also polled relatives and friends of marijuana users, most of whom noted memory loss and issues focusing in those who had used the drug frequently and on a long-term basis.
The study was published online at PNAS last year.