Here's How Long a Cannabis High Really Lasts, According to Science - ScienceAlert

This information can help inform advisory information given to patients, help recreational users make better decisions about performing tasks such as driving after consuming cannabis, and help update the laws to better reflect the reality of cannabis impairment.

How long the impairment lasted depended on three main factors: how strong the dose of THC is; whether the cannabis was inhaled or taken orally in the form of food, capsules, or drops; and whether the person was an occasional or regular user of cannabis.

Interestingly, regular users of cannabis can build up a tolerance, and perform better at cognitive tasks than occasional users after consuming the same amount.

"We found that impairment is much more predictable in occasional cannabis users than regular cannabis users.

Heavy users show significant tolerance to the effects of cannabis on driving and cognitive function, while typically displaying some impairment," explained behavioral pharmacologist Thomas Arkell, also from USyd.