Marijuana Can Lead To Lower IQ

People who were exposed to marijuana from a young age can have highly abnormal brain functioning and lower intelligent quotient, IQ. This is the findings in a study published in the journal ‘Acta Psychiatrica Scandinavica’.
The research was conducted by scientists in London and Ontario in Canada. Marijuana is the most commonly used illegal substance in the world.
Previous studies have suggested that frequent marijuana users, especially those who begin at a young age, are at a higher risk for cognitive dysfunction and psychiatric illness, including depression, bipolar disorder and schizophrenia. The use of marijuana did not correct the brain function deficits of depression, and in some regions made them worse.
“The study suggest that using marijuana does not correct the brain abnormalities or symptoms of depression and using it from an early age may have an abnormal effect not only on brain function, but also on IQ,” said Elizabeth Osuch from Lawson Health Research Institute, in Ontario, Canada.
“Many youth in our program use marijuana heavily and, despite past research, believe it improves their psychiatric conditions because it makes them feel better momentarily,” added Osuch, who is also the Medical Director of the First Episode Mood and Anxiety Program (FEMAP) at London Health Sciences Centre.
“For this reason, we decided to study the effects of marijuana and depression on psychiatric symptoms, brain function and cognitive function.”
Dr. Osuch and her team recruited youth in four groups: those with depression who were not marijuana users; those with depression who were frequent marijuana users; frequent marijuana users without depression; and healthy individuals who were not marijuana users.
In addition, participants were later divided into youth who started using marijuana before the age of 17 and those who began using it later or not at all. Participants underwent psychiatric, cognitive and IQ testing as well as brain scanning.
The study found no evidence that marijuana use improved depressive symptoms; there was no difference in psychiatric symptoms between those with depression who used marijuana and those with depression who did not use marijuana.
With past research suggesting a genetic role between marijuana use and depression, Dr. Osuch and her collaborators at Western University’s Robarts Research Institute also conducted genetic testing on participants.