In recent years, more and more states have legalized the use of cannabis for adults over the age of 21, with 20 states, including Delaware, currently allowing the recreational use of the drug. While using cannabis is legal, operating machinery or vehicles while high is still illegal under the same laws that criminalize drunk driving, as driving under the influence of any intoxicant poses a public safety hazard to others on and around the roads. While testing a driver for a DUI involving alcohol is relatively simple with a standard breathalyzer, few devices currently exist to quickly test for other varieties of intoxication. Current methods of testing for cannabis use examine urine, blood, and hair for remnants of metabolites produced as the body breaks down the active chemical, tetrahydrocannabinol (THC), and as such they can not be quickly carried out in a public, non-clinical area in the same manner as a breathalyzer test for ethanol intoxication. Furthermore, these tests indicate general patterns of cannabis use over the course of days or months, and can not be used to indicate a current state of intoxication within a period of a few hours. While these long term testing methods served employers and law enforcement in the days in which any consumption of cannabinoids was completely prohibited, and thus evidence that someone had consumed cannabis in the past month was as much of a fireable or criminal offense as evidence that someone was high on the job or while driving, these methods no longer work to determine the circumstances of a DUI or on the job intoxication when off the clock recreational use is permissible. In the past few years, researchers like those working at the company ElectraTect have started researching ways to more accurately test the concentration of THC in the human body in order to remedy these testing problems.
Structure of THC
While previous technologies for alcohol blood concentration testing have been available for decades, the many prominent chemical and metabolic differences between ethanol and THC in the body make constructing an accurate measuring device for cannabis intoxication much more challenging. Ethanol is measured via a simple oxidation reaction into an aldehyde that takes place in the sensor, and the amount of reactant hydrogen that is consumed in this oxidation is directly proportional to the concentration of the single, primary alcohol being tested. THC has an alcohol group on the side of a benzene ring, an ether contained in a cycloalkane ring, and an alkene group in a cycloalkane, all of which could accept a hydride ion, making the measurement of THC levels via oxidation reactions less linearly proportional to the levels of intoxicant present compared to the same measurements carried out on ethanol. The unique metabolism of THC is also a significant problem in measuring a current intoxication state either via breath tests or blood sample testing. Since ethanol is water soluble, the levels of ethanol in a person’s bloodstream directly correlate to the effects and duration of intoxication. Cannabinoids like THC are fat soluble, so THC blood levels spike and then drop rapidly while the person is intoxicated because THC exits the bloodstream rapidly and goes into fatty organs like the brain far more rapidly than ethanol, so a person with a low level of THC in their bloodstream could still be heavily intoxicated. Furthermore, these low levels of THC in the bloodstream persist for days after a cannabis user sobers up, as THC distributes from the bloodstream into fat in the body and is slowly released for days after usage. This unique metabolism means that a low level of THC in the bloodstream could be as indicative of a person currently being highly intoxicated via cannabis consumption as it could be an indication of a person who is currently completely sober but consumed cannabis several days ago. This makes disproving a DUI accusation via a blood test nearly impossible, as drivers who are sober but have used cannabis within the past week can still be charged with evidence of a positive drug test.
Antiquated legal codes also pose a significant barrier into research on how THC and other cannabinoids are metabolized in the human body. Due to a lack of prior research during the years in which cannabis consumption was completely outlawed, there is no standard measurement of what blood or breath level of THC counts as legally impaired, making DUI determinations much harder when the only measurement an officer can make is a subjective one of the driver’s behavior based on a few minutes of visual observation. There’s also the fact that federal laws still consider cannabis to be a schedule 1 drug despite the fact that only 3 states still completely prohibit its use, and since many researchers get most of their funding from federal grants, they face far more restrictions in research and the availability of testing materials for metabolic research on THC than they would on other potential compounds a person would reasonably ingest through food or medicine. These additional legal barriers have significantly slowed research into understanding how cannabinoids are metabolized and how they affect the human body. While groups like ElectraTect and academic researchers are testing various solutions to these problems, it will still likely be years before THC intoxication can be reliably measured and ascertained through measurable data beyond a subjective visual test on the part of a law enforcement officer.
This article generally portrays chemists in a positive light, as it shows how chemists are
trying to invent new devices and methods to help navigate an emerging concern for law
enforcement and legal professionals in determining the current state of intoxication a
person is operating under. The article mainly focuses on why there is not currently a
reliable method of testing THC intoxication, as many members of the public would
incorrectly assume that the process should be as straightforward as blood alcohol
testing. The article’s focus is on the challenges chemists must overcome in inventing
a new method of drug testing, and on how the changing attitudes around cannabis
use in the past decades has made older tests and federal level research guidelines
obsolete.
Posted by Elizabeth Smith
Source:
https://eu.usatoday.com/story/news/nation/2023/05/04/driving-while-
high-marijuana-breathalyzer-tests-could-help-detect-thc/70181882007/
THC Structure:
https://sensiseeds.com/en/blog/cannabinoid-science-101-what-is-cannabinol-cbn/
The difficulty with the title is that the conclusion is that we are a long way from really inventing a quick cannabis intoxication test. But I like the "Drive High" bit. It might have been better to call it something like "The Difficulty of ....." You give us a good summary of the scientific difficulties associated with such a test as well as the legal difficulties coming from the lack of such a test, or even a good standard for what constitutes intoxication. USA Today is a good widely read general interest source. The subject is certainly timely. Overall a good post.
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