The first systematic review examining the phenomenon of a ‘next day’ hangover caused by cannabis has found scant evidence impairment exists hours after consumption. The research, to be published in an upcoming issue of Cannabis and Cannabinoid Research, is available online ahead of print. While cannabis has been known to impair cognition and safety-sensitive task performance immediately after use, the question of impairment many hours or days after use has been unclear.
The researchers, from the Lambert Initiative for Cannabinoid Therapeutics at the University of Sydney, concluded that some lower quality studies reported ‘next day’ effects of THC on cognitive function and safety-sensitive tasks. However, most studies, including some of higher quality, found no such effect. Overall, it appears that there is limited scientific evidence to support the assertion that cannabis use impairs ‘next day’ performance. Further studies involving improved methodologies are required to better address this issue.