Frequent use of cannabis by young people can cause a reduction in IQ points according to a study by the RCSI University of Medicine and Health Sciences.
The study found that IQ scores reduced by approximately two points among those who frequently used cannabis over the course of the research compared to those who did not.
The study included 6,116 young people, 808 of whom used cannabis on at least a weekly basis, over a six-month period and 5,308 who did not use cannabis, according to the Irish Examiner.
Professor of Psychiatric Epidemiology and Youth Mental Health, Mary Cannon, said the findings reinforce earlier studies highlighting the harmful effects of frequent cannabis use on young people.
"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. Loss of IQ points early in life could have significant effects on performance in school and college and later employment prospects," said Prof Cannon.
According to the research, which involved a systematic review and statistical analysis of seven longitudinal studies, the decline in IQ predominantly related to a fall in verbal IQ points.
Clinical research fellow at RCSI, Dr Emmet Power said the research is vital in understanding the harmful impact cannabis can have on the brain.
"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," said Dr Power.
