APR 12, 2021 3:07 PM PDT

How Long Does a Cannabis High Last?

WRITTEN BY: Annie Lennon

With the growing number of low odor strains on the market and it being harder to detect whether someone is high, how long a cannabis high lasts can be very subjective. It is, however, an important matter when considering drug-driving laws which can penalize people for the presence of tetrahydrocannabinol (THC), a psychoactive substance in cannabis, in their system. As such, to facilitate public policy decisions, researchers have published a new study that may help determine how long the average 'high' lasts. 

"THC can be detected in the body weeks after cannabis consumption while it is clear that impairment lasts for a much shorter period of time," says Iain McGregor, one of the authors of the paper. 

"Our legal frameworks probably need to catch up with that and, as with alcohol, focus on the interval when users are more of a risk to themselves and others. Prosecution solely on the basis of the presence of THC in blood or saliva is manifestly unjust."

For the study, the researchers conducted a meta-analysis of 80 papers focused on cognitive impairment after consuming THC. The papers included data from 1,534 'performance outcomes' taken at various points while participants drove or completed comparable cognitive tasks after consuming cannabis.

Ultimately, the researchers found that how long the impairment lasted depended on three factors: the strength of the THC consumed; whether cannabis was inhaled or orally ingested as food; and how often the participants used cannabis. In particular, the researchers found that if orally consumed at high doses, cannabis could lead to impairment lasting up to 10 hours. 

Meanwhile, if consumed at lower doses via smoking or vaping, the effects could last for a more typical four hours. They also found that the kind of tasks performed also influenced how long impairment lasted. For simpler tasks, impairment seemed less significant, lasting for just four hours when inhaled. However, after inhaling higher doses of THC, participants could be impaired for up to six or seven hours while carrying out more complex tasks like driving. 

The researchers noted, however, that regular users of cannabis tended to perform better on cognitive tasks than occasional users consuming the same amount due to a build-up of tolerance. As such, they say it is not easy to predict how much cannabis would significantly impair a user and for how long its effects would be present. This is especially true for more regular users. 

Nevertheless, the researchers say that their findings suggest that most driving-related skills may return within 5 hours of inhaling cannabis. However, they did warn that more research is needed to assess time intervals for regular users to better understand how THC affects people on a broader basis. 

 

Sources: Science AlertScience DirectThe University of Sydney

About the Author
  • Science writer with a keen interest in behavioral biology, consciousness medicine and technology. Her current focus is how the interplay of these fields can create meaningful interactions, products and environments.
You May Also Like
NOV 07, 2020
Cannabis Sciences
Does Cannabis Make Bipolar Disorder Better or Worse?
NOV 07, 2020
Does Cannabis Make Bipolar Disorder Better or Worse?
While anecdotal evidence and some case studies suggest cannabis may benefit those with bipolar disorder, studies have re ...
NOV 19, 2020
Health & Medicine
Two Studies Raise Cannabis Heart Concerns
NOV 19, 2020
Two Studies Raise Cannabis Heart Concerns
Cannabis was under discussion at the American Heart Association’s Scientific Sessions 2020 (held November 13&ndash ...
DEC 14, 2020
Cannabis Sciences
Cannabis Users Need More Anesthetic During Surgery than Nonusers
DEC 14, 2020
Cannabis Users Need More Anesthetic During Surgery than Nonusers
Anecdotal evidence suggests that cannabis users require more anesthetic at the beginning of surgery than those who do no ...
FEB 19, 2021
Health & Medicine
Inhaling THC-Rich Cannabis Can Help Ulcerative Colitis
FEB 19, 2021
Inhaling THC-Rich Cannabis Can Help Ulcerative Colitis
Ulcerative colitis is a painful chronic condition in which the lining of the colon becomes inflamed and develops tiny op ...
FEB 25, 2021
Health & Medicine
Marijuana Legalization Link to Fewer Workers' Compensation Claims
FEB 25, 2021
Marijuana Legalization Link to Fewer Workers' Compensation Claims
A new paper produced partially under the auspices of the federal government and published by the National Bureau of Econ ...
MAY 01, 2021
Cannabis Sciences
Early Use of Cannabis Linked to Heart Disease
MAY 01, 2021
Early Use of Cannabis Linked to Heart Disease
While the dangers of cigarette smoking to cardiovascular health are widely known, those for cannabis have been less rese ...
Loading Comments...