The research, due to be published in an upcoming issue of Cannabis and Cannabinoid Research, is available online ahead of print.
Dr Danielle McCartney, a Research Fellow with the University of Sydney’s Lambert Initiative for Cannabinoid Therapeutics, led the analysis with colleagues Ms Anastasia Suraev, a Research Fellow, and Professor Iain McGregor, the Academic Director.
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.
To find out, the researchers evaluated 20 published studies investigating the effect the intoxicating component of cannabis, called tetrahydrocannabinol (THC), leaves on users more than eight hours after use.
This window known as the ‘next day’ effect encompasses any impact, including cognition or safety-sensitive task performance, beyond that eight-hour threshold.
“Most studies didn’t detect ‘next day’ effects of cannabis use, and the few that did had significant limitations,” Dr McCartney said.
“Overall, it appears that there is limited scientific evidence to support the assertion that cannabis use impairs ‘next day’ performance.
“Though, further research is still required to fully address this issue.”
