Frequent use of cannabis can lead to low IQ in adolescents: Study

You might think it’s cool and satisfying to smoke up, but did you know that cannabis use can make your IQ drop?
cannabis and IQ
Cannabis isn’t good for your IQ. Image courtesy: Shutterstock
ANI Published: 1 Feb 2021, 19:21 pm IST
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Most of us believe this myth that smoking cannabis rejuvenates the creative side of our brain and helps give us perspective. In fact, there are many young people who are lured into the trap of smoking up by this flawed philosophy. And instead of enhancing their creativity they end up with a falling IQ.   

Don’t believe us? Then read about this recent study that suggests adolescents who frequently use cannabis may experience a decline in their IQ over time.

Adolescents are more likely to use cannabis, noted the study

The findings of the research were published in the journal Psychological Medicine. The paper, led by researchers at RCSI University of Medicine and Health Sciences, provides further insight into the harmful neurological and cognitive effects of frequent cannabis use on young people.

The results revealed that there were declines of approximately two IQ points over time in those who use cannabis frequently compared to those who did not use cannabis. Further analysis suggested that this decline in IQ points was primarily related to the reduction in verbal IQ.

cannabis and IQ
Using cannabis-based products might not be a good idea. Image courtesy: Shutterstock

The research involved a systematic review and statistical analysis on seven longitudinal studies involving 808 young people who used cannabis at least weekly for a minimum of six months and 5,308 young people who did not use cannabis

In order to be included in the analysis, each study had to have a baseline IQ score prior to starting cannabis use and another IQ score at follow-up. The young people were followed up until age 18 on average although one study followed the young people until age 38.

“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,” commented senior author on the paper Professor Mary Cannon, Professor of Psychiatric Epidemiology and Youth Mental Health, RCSI.

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 Emmet Power, Clinical Research Fellow at RCSI and first author on the study.

cannabis and IQ
Marijuana and its connection to HPV-related cancers is enough to snatch its title of being a harmless drug. Image courtesy: Shutterstock

The study was carried out by researchers from the Department of Psychiatry, RCSI, and Beaumont Hospital, Dublin (Professor Mary Cannon, Dr Emmet Power, Sophie Sabherwal, Dr Colm Healy, Dr Aisling O’Neill, and Professor David Cotter).

The research was funded by a YouLead Collaborative Doctoral Award from the Health Research Board (Ireland) and a European Research Council Consolidator Award. 

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