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Can Using Marijuana Lower Your IQ?


marijuana cannabis lower iqFor many decades marijuana opponents would cling to the argument that smoking marijuana makes you stupid. These opponents would claim that marijuana use, by itself, would make an otherwise smart person an idiot. Marijuana opponents would completely disregard examples of very successful people that consumed marijuana, and try instead to use boogeyman tactics in order to scare people into thinking that marijuana significantly lowers the IQ of anyone that uses it.

Fortunately for intelligent marijuana consumers, science is on our side. In August of 2012 a study was released which claimed that marijuana use during teenage years, by itself, would result in a lowered IQ by middle age. I remember when this study was released because I wondered how it could be considered scientifically sound, considering how many things determine an IQ by the time a person is middle aged. A lot of things occur during the years between being a teenager and being middle aged that would affect how smart you are.

The brain is a lot like a muscle in that it needs to be exercised often, and in the right way, to ensure that it is performing optimally. If a person started out with a high IQ during their teenage years, yet did nothing to exercise their brain for decades, they obviously wouldn’t be as smart as if they had kept their brain fit during those same years. There are many things that can kill your brain cells during the adult years of your life, and they would all contribute to changes in your IQ level.

The data from the previously mentioned study was reviewed about a year ago, and the results of the review have been making their rounds on social media lately. The review found that the original study had ignored other contributing factors to a decline in IQ from teenage years and middle age years. According to the review:

“Mitch Earleywine, a psychologist at the University at Albany, State University of New York, says that Røgeberg’s analysis definitely supports the idea that links between adolescent cannabis use and drops in IQ are essentially spurious, arising from socioeconomic differences rather than any sort of pharmacological action.”

Did you start smoking marijuana during your teenage years? Are you middle aged now? How do you feel? Do you feel that you are not as smart as you used to be? If you are like me, you likely feel smarter now than you did when you were a teenager. I know there are some activities where consuming marijuana seems to enhance my IQ for those particular activities. I have always felt that marijuana tickles a part of my brain that doesn’t operate as well without marijuana, and that it’s the part of my brain that controls my creativity level. Anyone else feel the same? Below is one of my favorite memes that deals with marijuana and being smart/dumb:

marijuana lower iq


About Author

Johnny Green


  1. Immortal Illumined on

    the greatest plant in the universe is almost free, LET FREEDOM RING!!!13

    from 0 states to half the country, from low 20% approval to almost 70%…marijuana is revolutionizing the planet…again

    iq is overrated…heart and soul are much better, and easily touched by this plant


  2. I was 11 when I first started smoking cigarettes & 13 when I started smoking pot, now I’m almost 60. I still have learning problems & probably always will. When I started smoking pot, it seemed like I could finally understand what the teacher was saying & trying to explain to me. I never did think I was dumb. It was always other people telling me that I was dumb that put me into that; I want to make everyone like me, place. Now, I only try to make myself happy. You, yourself can’t make others happy; they have to do that for themselves. Just a personal observation.

  3. Another marijuana meme with all men. Bummer. Would you say that all these guys are introverts? Just curious…

    IQ is another one of those tests/rating systems that I have doubts about. I find it ironic that we think we are smart enough to actually design a test that would rate a person’s intelligence level. (Here, this number tells you how smart you are.) Seems too simplistic to me. But then, I don’t know my IQ. If anyone wants to publish their number…

  4. Great article. The crux of the initial study’s failure was that the authors totally ignored socioeconomic factors. Anyone who knows even a little bit about childhood development knows that the number-one predictor of IQ was, is, and probably always will be socioeconomic status. Kids from poor families don’t perform as well in school as rich kids. Period. You’re supposed to stratify samples based on mediating and moderating factors that you already *know* influence the dependent variable being studied so that you ONLY study the supposed influence from the independent variable you’re interested in — in this case, socioeconomic status strongly influences IQ and the authors should have stratified by SES to see what influence cannabis has on IQ, separate from SES.

    When you *do* stratify the sample by SES, there is no statistically significant difference in IQ between the cannabis group and the non-cannabis group. The drop in IQ they alleged completely vanishes.

    I can’t say if the error was on purpose, but if they *did* deliberately omit SES simply to vilify cannabis, I can’t help but laugh at the irony. That little deception would only succeed if cannabis advocates actually WERE made stupid by cannabis. But their ***own data*** (when analyzed correctly) says that is NOT the case! Frankly, it’ll be hard not to laugh next time some slack-jawed prohibitionist tries to tell me how cannabis makes us stupid, especially if they reference that flawed study.

  5. Wish I couldve been tested then. Im 46 now and have learn more sittn in front of a computer smokin than what I did sitn in a classroom from a book. Alot of teachers like to teach by their opinions rather than whats needed. And we all know what they say about opinions

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