Marijuana and Motivation: Fact or Fiction?


There is a pervasive belief that using cannabis can make you lazy. But is there any truth to it? A new study from the University of British Columbia has set out to find an answer.

Rats are industrious little creatures. Smart too. But when researchers at the University of British Columbia administered THC, something very curious happened – the rats became cognitively lazy.

In a study published in the Journal of Psychiatry and Neuroscience, it was found that consumption of THC (tetrahydrocannabinol, the main psychoactive ingredient of marijuana) resulted in lab rats becoming less willing to try cognitively demanding tasks.

Interestingly, it wasn’t that they suddenly became unable to carry out the tasks; they just didn’t want to.

As one of the study’s authors, Mason Silveira, said, “There is also research pointing out that sometimes THC doesn’t affect all your cognitive abilities across the board. What’s interesting in our study is that it seems to primarily affect your ability to decide or choose whether you want to exert that cognitive ability.”

What Did the Study Involve?

The study sought to understand the effects of THC and CBD (cannabidiol) on a rat’s willingness to think about, and undertake, a task.

Twenty-nine rats were trained to perform in an experiment involving an easy challenge and a difficult challenge with the reward of a sugary treat on offer for successful completion of the task.

Usually, these rats would prefer to take on the more difficult challenge due to the fact that there was a bigger reward at the end of it. However, when they were given THC, their desire to take on the harder challenge diminished, and they switched their attention to the easier tasks, even though there was a smaller reward on offer.

The researchers then looked at the effect of CBD on the rats. CBD is, of course, an active ingredient in marijuana, and one of the most abundant, along with THC. 

Researchers found that there was no adverse impact from CBD on the rats’ decision-making skills or attention span. However, they also observed that it did not block the negative effects of THC – something that it was previously thought to do.

The senior author of the study, and associate professor in UBC’s psychology department, Catharine Winstanley, admitted that this was surprising to the researchers. It had been previously suggested that a high concentration of CBD could moderate or reduce the psychoactive effects of THC.

The outcome of the study has proven interesting due to the very simple fact that cognitive exertion is fundamentally crucial to success in all walks of life. The researchers were therefore keen to point out that diminished willingness to engage in difficult and challenging tasks is a concerning side effect of cannabis use.

How Did the Experiment Work?

It’s probably worthwhile briefly outlining how the experiment worked as picturing rats choosing between an easy and a hard task is probably conjuring all sorts of Pixar-esque hijinks in your mind.

Essentially, the intrepid lab rats were presented with two levers from which to choose. By selecting a specific level, they were effectively signaling whether they wanted to take on the easy challenge or the hard one.

In the easy challenge, a light turned on for one full second. The rats would then detect the light and respond to it by poking it with their nose. After successfully completing this task, they would receive one sugar pellet as a reward for their endeavors.

The more challenging task resulted in the light being turned on for only 0.2 seconds. If the rats responded to the light with a nose poke, they received two sugar pellets for their sharp reactions and unwavering attention span.

If that vivid description still hasn’t done the experiment justice, then you can watch it in action below:

The Future of Marijuana and Motivation

The results of this experiment aren’t exactly overwhelmingly positive, but they shouldn’t be used as a stick with which to beat the medical marijuana industry.

While advocates will always defend their belief that marijuana can cure and/or treat a whole manner of maladies – and critics will always suggest that cannabis use is a gateway to more nefarious drug use – the findings of this study unequivocally highlight the need for more research into the impact of THC on the human brain and how it alters our decision-making abilities. And that shouldn’t be a bad thing.

Against a Backdrop of Change

The results of this UBC study have been published against a changing landscape when it comes to cannabis in Canada. Since the end of August, Canadians can now avail themselves of new rules and grow their own medical marijuana at home for personal use as opposed to buying it from licensed growers.

The new rules also mean people who are authorized by their doctors to use medical marijuana can also delegate the growing and cultivation to another person.

These regulations came about as a response to a Federal Court decision earlier this year that found the ban on patients growing their own medicinal cannabis to be a violation of their constitutional rights. The decision by the Federal Government to legalize the growth of medical marijuana at home has been backed by both the Canadian Medical Association and the Centre for Addiction and Mental Health.

These groups have both said that the combination of legalization and strict regulation when it comes to cannabis would be the most effective way of reducing its observable detrimental effects, such as this issue of marijuana and motivation.

With attitudes changing and strides being made in terms of legalization and regulations, the study by the team at UBC could actually encourage further research and, ultimately, the cultivation of an even more beneficial strain of medical marijuana in the not-too-distant future.


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