Lab rats suffer from laziness after being administered marijuana, a new study has found. According to a report by University of British Columbia researchers published in the Journal of Psychiatry and Neuroscience, after being given THC – the main psychoactive ingredient in marijuana – rodents were less likely to try cognitively demanding activities. Under the study, 29 lab rats were used to test the effect of THC and cannabidiol (CBD) and how it correlates to their willingness to exert cognitive effort. During the experiment, rats had to choose between the cognitively challenging task of responding to a light for 0.2 seconds by touching their nose. An easier task required them to touch their nose while the light stayed on for just one second.