New research shows how long it takes for cannabis damage to subside

New research has shown for the first time how long cannabis users are likely to be affected and when it can be safe for them to drive.

The findings, say researchers and supporters, bolster the argument for changes to drug trafficking laws in much of Australia.

Researchers at the Lambert Initiative for Cannabinoid Therapeutics at the University of Sydney found that users were affected for three to 10 hours after taking moderate to high doses of the intoxicating component of cannabis, tetrahydrocannabinol (THC).

THC can be detected in the body for weeks after cannabis use, which means that users may face fines and loss of license, despite the fact that they are not affected by the drug.

The research, published in Neuroscience & Behavioral Reviews, looked at 80 scientific studies on the effect of THC on driving performance over the past 20 years.

It was found that the exact level of damage depends on the dose, whether THC was given orally or by inhalation and how often the medicine was taken, among other factors.

“Our analysis indicates that the damage can last up to 10 hours if high doses of THC are consumed orally,” said study lead researcher Danielle McCartney.

However, a more common duration of damage is four hours, when lower doses of THC are consumed through smoking or vaporization and simpler tasks are undertaken.

The study also found that regular cannabis users became less affected by THC than those who used cannabis occasionally.

Dr. McCartney said people could be affected for six to seven hours if they inhale higher doses of THC and evaluate complex tasks, such as driving.

Her research is the first comprehensive meta-analysis that puts a time frame on impairment.

“Our evidence should help people make informed decisions and policy makers adopt evidence-based policies and tell people how long they should wait before driving,” she said.

The Therapeutic Products Administration (TGA) has approved 100,000 prescriptions for medicinal cannabis in Australia.

Lambert Initiative’s academic director, Iain McGregor, said medical cannabis users are particularly interested in knowing when it is safe for them to drive, despite the fact that the law is clear.

You have a massive amount of prescription drug that goes into people who are told, ‘You can’t drive at all, you can’t have a single molecule of THC in your system,’ which is, you know, just ridiculous. “Professor McGregor said.

“THC can be detected in the body weeks after cannabis use, while it is clear that the damage lasts a much shorter period of time. Our legal frameworks probably need to come to an end.”

Former magistrate David Heilpern said the investigation showed that roadside drug testing laws needed to be changed.

Mr Heilpern retired early, partly because of his frustration at seeing so many patients with medical cannabis lose their license and sometimes their livelihoods after being caught driving with small amounts of THC in their system.

“We had a situation where people took their medications as prescribed, did not drive in any negative way and still lose their license, were fined and received a criminal record,” he said.

“I started driving home from work, thinking, I just can’t do that.

Mr Heilpern said cannabis is the only prescription drug in Australia that you can take, but you can’t even drive it at a detectable level.

He is part of the Alliance for Cannabis Law Reform, which advocates for changing state laws, offering drug cannabis users a defense if they test positive for a roadside drug test.

The defense already exists in Tasmania and there are bills before the parliament in Victoria and South Australia. The NSW Parliament rejected a bill on the issue in October.

“In NSW, we already have this law because it applies to morphine,” said Mr Heilpern.

“If you have a detectable level of morphine in your system and you can show that you have a prescription for it, then you have a defense.

“All we have to do is do this for cannabis. It’s a very simple amendment and it solves the problem.”

Gino Vambaca, co-founder of Harm Reduction Australia, said Australian laws have punished people for past drug use, not insecure driving.

“It’s no longer a road safety campaign, it’s a detection and penalty campaign,” he said.

“We do not tolerate people who use drugs and drive, but what we are saying is that there is no attempt by the police to measure even the deficiency.

“We need to tell people who use medical cannabis, ‘You want to drive or you want to relieve your pain, because you can’t do both.’

“And this is a horrible choice for them, which they have to make.”