Teenagers who frequently use cannabis have lower IQ test scores a few years later.
- Young smokers have on average a 2 point drop in their IQ over time compared to those who do not use.
- This drop in IQ points is mainly related to the reduction in verbal IQ.
Consuming cannabis early and regularly damages physical and cognitive health. A recent study found that it increases the risk of depression, addiction and isolation at age 35. New research by Irish scientists from the University of Medicine and Health Sciences RCSI provides further insight into the harmful neurological and cognitive effects of frequent cannabis use on young people. Published on January 27 in the magazine Psychological Medicineit reveals that adolescents who frequently use cannabis are more likely to experience a drop in their intelligence quotient (IQ) over time.
Significant effects on school and future jobs
The study suggests that young smokers have an average drop of 2 points in their IQ over time compared to those who do not use. Further analysis suggested that this drop in IQ points is mainly related to the reduction in verbal IQ. The research included a systematic review and statistical analysis of seven longitudinal studies involving 808 young people who used cannabis at least once a week for at least 6 months. The results were compared with those of 5,308 young people who had not used cannabis. Young people were followed up to age 18 on average, with one study up to age 38.
“Previous research tells us that young people who use cannabis often have worse life outcomes than their peers and are at increased risk for serious mental illnesses like schizophrenia.said the paper’s lead author, Mary Cannon, professor of psychiatric epidemiology and youth mental health at RCSI. Losing IQ points early in life could have big effects on school performance and college job prospects later.”
Worrying results
These results confirm the harmful effects of cannabis use in young people, when their brains are forming. “Cannabis use among young people is of great concern as the developing brain can be particularly vulnerable during this periodconcluded Dr. Emmet Power, clinical researcher at RCSI and first author of the study. The results of this study help us better understand this important public health issue..”
