Does Marijuana Use Decrease IQ?

Frankly speaking I have never been a fan of IQ tests; this is because I find these standardized tests to be rigid and limited in being able to fully account for the complexity of the average human mind.

This being written, a recent study of a thousand people in New Zealand conducted over a period of twenty years claims that when people use marijuana for a period of time prior to their eighteenth birthday, they experience a permanent and significant drop in their IQ. You can read more about the study here on BBC.

Further, they claim that the more people smoked, the greater the loss they experienced in IQ and that stopping or reducing consumption of marijuana failed to fully restore lost IQ.

As a therapist who has been practicing for the past eleven years, I can tell you this; marijuana is bad for you at any age. Yes, it is more damaging to the brain during the teenage years because the brain is going through a great deal of changes, most notably pruning connections between brain cells and synapses to enable the brain to become more efficient during the adult years.

It’s no surprise that the teen years are when people start to embrace a specialty or two. With marijuana use, I have noticed clients are not motivated towards solving their problems, most likely due to the fact that during their period of using they are not noticing their problems.

While it makes sense to stipulate that IQ can never be truly restored even with reduced consumption of marijuana, I don’t believe that loss of problem solving abilities can never be fully restored after stopping the use of marijuana.

I have seen clients make a hundred and eight degree progress in regards to addressing their issues and attaining goals (problem solving) after ten consecutive months of ceasing use. Granted, if you are dealing with someone who has been using for over twenty years it will take a lot longer than ten months for you to notice significant progress. Assuming they want to stop in the first place.

Personally I don’t believe the researchers allowed enough time to lapse before testing subjects who had stopped using. Then again, traditional IQ tests are too rigid and limited in their ability to truly measure the complexity of anyone’s level of intelligence.

Either way, marijuana is still bad for the brain.

If you feel in anyway agreeable or annoyed by this post, please feel free to leave your comments in the comment section. I do read all comments, also please be civil in your comments.

Ugo is a psychotherapist based in Tucson Arizona, who specializes in anger management. He is also the author of Anger Management 101-Taming the Beast Within.