Scientists, apparently bored with pert, productive rats, added a little marijuana to the equation and found that, as many a teenager can tell you, laziness ensued. So report researchers at the University of British Columbia in the Journal of Psychiatry and Neuroscience after concluding that male lab rats given TCH experience an observable reduction in their "willingness to exert cognitive effort." To test this, researchers trained 29 rats to choose whether they wanted to perform a more difficult task to earn a larger quantity of a sugary treat or perform an easier task but earn less of the treat. Without THC, most of the rats preferred to exert themselves for the greater reward; after the dose of THC, however, they largely chose the easier path and settled for a smaller treat, even though their ability to perform the harder task was not impacted.
"What’s particularly interesting is though they were less likely to do these more difficult tasks they were still able to," one researcher tells the Guardian, adding that there's a clear need for more research on how THC impacts the human brain, whether any negative side effects can be reduced, and whether marijuana compounds other than THC play a role. When the researchers gave the rats doses of the non-psychoactive compound cannabidiol, or CBD, which is thought to have medical benefits such as pain relief and doesn't cause a high, they found that it didn't impact the rats' cognitive behavior, but it also didn't help mitigate the effects of THC on motivation. (Here's what a legal pot habit will set you back just south of the border in Washington state.)