Does Weed Use Lower Your IQ?

While cannabis can provide plentiful medicinal benefits, are there negative side effects from using it too often?

We note that the subject contained in this article represents illegal activity in certain jurisdictions. Whilst we do not condone any acts which are contrary to any such laws, we understand that readers in those jurisdictions which have decriminalised cannabis may find this article of interest.

Just fifty years ago, America began enacting its 'War on Drugs' which saw the use of drugs come with some heavy penalties within the United States. Most countries similarly began to ban most substances, leaving little other than tobacco and alcohol to be legal for consumption.

Now, as we look around the world, the War on Drugs is finally coming to an end, with cannabis becoming legal in an increasing number of countries.

In fact, as the COVID-19 pandemic rages on, we're seeing some interesting developments or approaches towards drug use and legalization, particularly when it comes to cannabis. Both the United States and Canada have deemed the cannabis industry "essential," and in recent weeks, cannabis sales have been at unprecedented levels. Moreover, despite global lockdowns in place, 4/20 still went off (albeit virtually) without a hitch.

Now countries like Lebanon are looking toward cannabis as a way to revitalize their economy amid the downturn that is occurring during COVID-19, after having seen the job growth and tax revenue generated in countries like the U.S.

Evidently, the War on Drugs has failed, and people are turning to cannabis not only for these aforementioned economic benefits but also for medicinal benefits, in alleviating symptoms related to epilepsy, Parkinson's, Alzheimer's, chronic pain and so on.

So are there any downsides when using cannabis? Specifically, how does cannabis use impact one's IQ level? Let's take a look.

What is IQ?

IQ stands for intelligence quotient and is the score you get at the end of an IQ test or standardized test. IQ represents an individual's capacity to process information, and how capable one individual is when compared to others that have taken that same test.

As a result, IQ is a powerful statistical predictor of multiple future life outcomes, including income and educational attainment, particularly when one's IQ is paired with their socioeconomic status (SES.) Perhaps most interestingly, IQ can also determine one's longevity and health, and those with higher IQs are less likely to die earlier.

Evidently, IQ is a pretty powerful metric, and as such, individuals want to avoid behaviours which might risk lowering their IQ level as it may result in a lower quality of life. Things like stress, obesity, sugar and excessive alcohol consumption can all assist in reducing the IQ of individuals. But what about cannabis? Can weed use lower IQ? This is a claim made by several high-level individuals such as Michael Bloomberg, Donald Trump, and Dr. Phil, who each have mentioned the potentially deleterious effects of cannabis consumption.

Let's take a look at the effects of cannabis use on one's IQ.

How Weed Affects Your IQ

With the stigma surrounding marijuana finally wearing off, and dispensaries becoming more prevalent across the globe, more and more people are likely to become cannabis consumers. However, due to the federal illegality of the plant, much research has been stifled with regard to the effects that cannabis use has on the body.

So what do we know about cannabis and IQ? Can people toke up before taking a test?

Well, the jury remains very much out on this subject, with some studies saying that cannabis does lower your IQ, and others saying that no, it doesn't.

The primary study cited attributing cannabis use to a decrease in IQ levels comes from Dunedin in New Zealand in 2012, which followed a cohort of 1,037 individuals from birth up until they were aged 38. The study involved performing neurological tests on the cohort throughout their lives, including at age 13, prior to cannabis use, and at age 38, after cannabis consumption patterns had developed.

The Dunedin study found that consistent cannabis consumption throughout one's life was associated with a neurological decline across several domains of functioning, producing more cognitive issues for those that smoked weed. Perhaps even more damning than that fact, was also that when users ceased their cannabis consumption, their cognitive functioning did not fully return – particularly in the case of those who had consumed cannabis as adolescents. In fact, their IQ dropped by 6 to 8 points permanently.

Though if you're reading this and freaking out while smoking a joint, don't freak out just yet, there's another study which seems to disagree with the Dunedin study – this time, involving twins.

The Twin Study

The twin study, carried out in 2016, involved 614 families of twins and triplets the greater Los Angeles area school districts. The study lasted over 10 years, with most twins aged 9-10 at the beginning of their involvement with the study, being assessed roughly every two years. Families involved in the study were from a wide range of ethnic as well as socioeconomic backgrounds and were deemed to be representative of the greater LA area.

Throughout the study, sets of twins were asked to self-report their cannabis consumption, and the twins with divergent or discordant marijuana use were closely examined. From there, the IQ scores were observed, among both the twin that did consume marijuana regularly and the one that didn't, in order to gauge any notable differences in cognitive abilities.

Interestingly, the study reported that there was "little evidence to suggest that adolescent marijuana use has a direct effect on intellectual decline."

This is particularly interesting given that the longitudinal twin study controlled for socioeconomic status, ethnicity, and genetics to the greatest possible degree, leaving the effects of cannabis use versus non-use to be quite clearcut.

All-in-all, there is still a lot of room for further investigation into the effects of cannabis upon one's cognition and IQ, with some sides suggesting its harmful, and others suggesting the complete opposite.

The one certainty is that, as is the case with all substances, misuse and binging is never a good thing. Be responsible with your cannabis use, and perhaps in the future as legislative hurdles continue to be removed from the cannabis landscape, we will one day see concrete evidence for the effects that cannabis has upon IQ.

Get the Latest Marijuana News &
Content in your Inbox!

All your support helps The Green Fund keep writing content for all you
marijuana enthusiasts and potential pot stock investors

Louis O'Neill
Louis O'Neill

Louis is a writer based in Sydney with a focus on social and political issues. Having interviewed local politicians and entrepreneurs, Louis now focuses on cannabis culture, legislation & reform.

There is 1 Commentin this post

  1. Would just like to point out first that weed will obviously affect everyone differently, but in my case I would argue that it has not negatively impacted my intelligence. I have smoked/vaped cannabis for over 20 years, starting out with weekend adventures in my early teens and then progressing to a daily consumer over the last 15 years.

    I graduated from university a few years back with a degree in finance and economics, GPA of 6.76
    I won numerous awards for achieving the highest grade in a number of subjects and the award for highest GPA in my graduating year.

    I'd also like to add that I have worked in a hydroponics store for over 3 years now. I like to joke (but it's true) that I do much less damage to society working there than at a bank. During my time there, I have been told by at least 5 customers that they, or someone close to them, had greatly reduced or even completely removed cancerous tumors from their body.

    There is a monumental amount of anecdotal evidence (and some scientific evidence that was conveniently swept under the rug!) out there supporting the extreme view that something in cannabis, perhaps THC, can reduce cancerous tumors in certain instances.


Leave a Reply

Your email address will not be published. Required fields are marked *