Scientists Still Looking For A Reliable DUI Test For Marijuana

Recent years have seen numerous milestones when it comes to the use of marijuana and it’s perception around the United States. Not only is Marijuana nearly as socially accepted as alcohol in today’s world, its recreational use is now legal in six states, including Colorado. Ironically, its legal status creates a new problem for law enforcement, stopping and charging drivers high on marijuana.

“It’s a brave new world,” declared Chris Halsor, a Denver lawyer and former prosecutor in reference to Colorado’s recent laws which legalize marijuana’s recreational use.

To train law enforcement for this new problem, police officers are partaking in new training exercises and activities which would help them better identify drivers high on marijuana. One such training exercise took place in spring this year with 16 state patrol officers from Colorado and Wyoming. The exercise involved the officers going shopping at legal marijuana dispensaries to examine different marijuana products and paraphernalia.

The second part of the exercise involved four volunteers consuming large quantities of marijuana provided by law enforcement. The point of this part of the exercise was to show the officers signs of marijuana inebriation and to gauge whether tests they use to identify drunk drivers also work on drivers who are high on marijuana. The results lacked consistency though, because all the volunteers performed differently on different tests. For example, a volunteer named Christine did well on math but didn’t do well on tests such as balancing, remembering instructions or measuring time. Officers also decided that if they had pulled Christine over, they would have arrested her because she would be a danger behind the wheel. However, they couldn’t say the same for other participants who had smoked just as much marijuana.

The problem with marijuana is that despite the increasingly legal use of cannabis in many states, police officers still don’t have the equivalent of a reliable alcohol breathalyzer or blood test — a chemically based method of estimating the level of inebriation caused by the drug. A blood test exists that can detect some of marijuana’s components. However, in case of marijuana, there is no widely accepted, standardized amount in the breath or blood that gives police or courts a good sense of who is considered impaired. Hence, the decision of whether to charge someone for driving while under the influence of cannabis is up to the police officers best guess.

There is a national effort underway by scientists to create a device that would work the same way for marijuana as breathalyzers do for alcohol. One of these is chemical engineer Tara Lovestead, who is working on setting chemical standards for what a marijuana detection test might require. However, Lovesteads’ research is hindered by the federal scheduling of the drug. Since cannabis is still a schedule 1 drug, meaning the federal government considers it a substance “with no medical use with a high potential of abuse,” she cannot use marijuana for her research, despite the fact that her research facility is located in Colorado.

“We cannot use the stuff down the street,” bemoaned Lovestead.

In states like Colorado, there is a THC blood test that law enforcement uses to show “presumed” impairment. If a person has more than 5 nanograms of THC per millilitre of blood, a court or jury can infer them to be impaired.

But Lovestead and others maintain that, scientifically speaking, that figure is quite meaningless.

“We just don’t know whether or not that means they’re still intoxicated, or impaired or not,” she said. “There’s no quantitative measure that could stand up in a court of law.”

Whereas ethanol, the chemical in alcoholic drinks is water soluble and is hence quickly distributed throughout the body and flushed from the body after a few hours, THC is fat soluble and can linger in the body’s fat stores for a long time, depending on a number of variables.

One particular marijuana study involved 30 frequent marijuana users staying at a facility with no access to marijuana for a month. Researchers saw that the heavy users were showing levels above 5 nanograms of THC per milliliter of blood for several days after they had ceased using marijuana.

“And it shocked everyone, including ourselves, that we could measure, in some of these individuals, THC in the blood for 30 days,” says Marilyn Huestis, a toxicologist with the University of Maryland School of Medicine who recently retired from leading a lab at the National Institute on Drug Abuse.

On the other hand, another study showed that people who weren’t regular users could smoke a joint right in front of the researchers and show no evidence of cannabis in their blood reports.

So, in addition to being invasive and impractical, a blood test is also a poor measure for how inebriated a person is from marijuana use. In light of this, some scientists have turned to breath testing in hopes of creating something of use. Companies such as Cannabix Technologies and Hound Labs are currently in the process of creating devices that can measure the concentration of THC in a person’s breath to check if they have recently smoked marijuana. This is a difficult task as THC and other compounds present in cannabis have a very fleeting existence in the air. Luckily, Tara Lovestead specializes in finding trace quantities of compounds in the air. She and her team have worked on methods to use tiny air samples to detect evidence of arson, buried bodies and hidden explosives. Marijuana is the next challenge.

As things are progressing right now, the decision to charge drivers with being high on cannabis rests with the police officers best guess.

“It’s one of those subjective areas,” says Colorado State Patrol officer Rich Armstrong.

“It’s too subjective,” argues Tara Lovestead.

News Source: www.NPR.org



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