If you reject the myth that marijuana makes people lazier, you may be surprised to learn it’s not such a myth, at least according to a new study out of Canada.

The report, released in August by scientists at the University of British Columbia, found that THC, the primary psychoactive chemical in cannabis, made rats sluggish and lazy. The experiments didn’t provide conclusions about whether human users experience a similar lack of ambition, but researchers said it’s likely.

The idea that pot leads to laziness is not new; stoners have carried the reputation for decades. But science on the subject is scarce, leaving experts with little proof one way or the other. Previous studies show marijuana can cause “physical laziness,” for example by killing ambition needed to decide to get off the couch, but few scientists have examined the drug’s impact on cognitive function.

Cognitive function in rats was tested

To test whether THC increases “cognitive laziness,” lead author Mason Silveira and his team trained 29 rats to choose between two tasks, one hard, one easy, both rewarded with a treat. The more difficult task produced a tastier reward.

For example, when the rats reacted to a light that flashed for a full second, they got a single sugar cube. When they reacted to a light that flashed for just 0.2 seconds at a time, they got two lumps. The rats completed the experiment four times: once with no marijuana, once after receiving a dose of THC, once with CBD, and once with both chemicals.

THC and CBD are the most critical cannabinoids in marijuana. THC produces the high that recreational users seek, while CBD has a wide range of non-intoxicating medical uses.

Rats chose easier task under influence of THC

Under normal conditions, the rats usually picked the harder task, earning the sweeter reward. But when the rats were under the influence of THC, they took the easier route, the study found, even though it meant less sugar.

“Perhaps unsurprisingly, we found that when we gave THC to these rats, they basically became cognitively lazy,” Silveira said. “What’s interesting, however, is that their ability to do the difficult challenge was unaffected by THC. The rats could still do the task, they just didn’t want to.”

The team behind the study explain their findings in more detail in the video below.

Rats chose easier task under influence of THC

In other words, couch lock may be more a matter of choice than necessity. Any pot smoker who has been caught in a cycle of binge-watching Planet Earth might disagree, but the study suggests THC may in fact muffle ambition and enthusiasm.

Interestingly, researchers reported that CBD did not have the same effect on the rats and failed to prevent the cognitive deficits linked to THC. After consuming CBD without THC, rats chose the harder task; after consuming both together, they picked the easy one. Silveira said his team was surprised by this finding, since earlier studies showed CBD could counteract the cognitive effects of THC.

Tell us: Does it make any difference to you that marijuana may cause laziness? Do you have a strategy for staying busy while toking? Leave a comment below.

state marijuana laws