Cannabis in America

Shocker: Weed Makes Rats Lazy AF, Say Researchers

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A new study from the University of British Columbia suggests that there is some truth to the stereotype that smoking weed makes you lazy–at least as far as rats are concerned.

Researchers published a study in the Journal of Psychiatry and Neuroscience, that found THC, the main psychoactive ingredient in marijuana, made male rats less likely to choose more cognitively demanding tasks. (Presumably they used male rats because all the female rats were already busy multi-tasking three things at once.)

UBC conducted the study by training 29 lab rats to complete behavioral tasks where they had to decide whether or not they wanted to engage in a task that required a lot of attention for a larger reward, or complete an easier task for a smaller reward.

Under normal circumstances the rats opted for the harder task to earn the bigger reward. However, when the scientists gave the rats doses of THC and had them pick between the same tasks, they chose the easier tasks for the smaller reward–basically they became “cognitively lazy.” Surprisingly, the rats could still perform the harder task, they just didn’t want to.

Some of the motivations behind the study were to determine whether or not marijuana legalization has an adverse effect on the quality of life of its users. The researches concluded:

We hypothesize that associations between THC and poorer life outcomes may be due to a drug-induced decrease in willingness to allocate cognitive effort, rather than impairments in fundamental cognitive abilities per se. Our findings also suggest that unlike THC, CBD does not adversely affect executive function, and as such its inclusion in medicinal cannabis is not of primary concern.

While the results of this study probably aren’t shocking for most of us, they do provide more information about the affects of THC–at least on rats. Although, I do think they could have gotten the stoned rats to try a little harder if they’d offered them pizza as their reward instead.

Watch the researchers explain the study below


Alexis Evans
Alexis Evans is an Assistant Editor at Law Street and a Buckeye State native. She has a Bachelor’s Degree in Journalism and a minor in Business from Ohio University. Contact Alexis at



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