Researchers at the National Institute of Justice found that “although THC has been proven to affect areas of the brain that control movement, balance, coordination, memory and judgment – skills required for safe driving – THC levels in biofluids were not reliable indicators of marijuana intoxication for their study participants.”
According to the study's results, many of the participants had reported significantly decreased cognitive and psychomotor functioning even when their blood, urine and oral fluid contained low levels of THC.
The researchers also observed that standardized field sobriety tests – such as the one-leg stand, walk and turn, and modified Romberg balance tests – commonly used to detect driving under the influence of drugs or alcohol, were not effective tools for the detection of cannabis intoxication.
The study’s results complicate the enforcement of police laws against driving under the influence of cannabis and could essentially bury the so far quickly developing commercial field of THC testing kits.
One such test – “Drugwipe,” a saliva-based drug test which was developed by Securetek – was selected last month to go into official use after a years-long tender by Israel Police.
Drugwipe works similarly to a pregnancy test, giving police a yes or no answer regarding the existence of certain drug levels – in this case, an as-of-yet undetermined amount of THC – in a person’s saliva. If they test positive, they are sent to the police station to receive a more comprehensive blood test.
However, the results of the study seem to indicate that both tests could be completely unreliable factors in determining whether someone is capable of driving.
While the product can detect up to seven different kinds of drugs, its main intended use was for the detection of THC.
Now that the study essentially nullifies the main purpose of Securetek’s technology, the official importer chosen for the project, Dolphin Medical – an offshoot of the larger Shizim company, whose CEO is former Mossad chief Tamir Pardo – are looking to see whether Israel Police will indeed end up adding the product to their protocols.
PSYCHIATRIST PROF. Shaul Lev-Ran, Co-founder of the Israel Center on Addiction spoke with The Jerusalem Post on Monday to explain the likely reasons behind the study’s results.
Lev-Ran explained that while alcohol is one specific substance, allowing development of effective breathalyzers, cannabis is a complex plant composing of over 100 different cannabinoids and 400 different terpenes which make the development of similar breathalyzers substantially more complex.
He added that the metabolic rate for cannabis users varies widely, meaning that while one person may need to wait 4 hours following cannabis consumption before driving, someone else may need yo wait twice as long.
Cannabis is also unique in that it does not leave the human bloodstream as quickly as other drugs, especially its relatives in the psychedelic family. While compounds like LSD and psilocybin normally leave the bloodstream within a day or two, heavy cannabis users can often find cannabis in their blood even a month after use.
“Right now, science doesn’t have an accurate way of measuring how long after cannabis consumption someone would need to wait before it is safe for them to drive again.”
Lev-Ran said developing effective roadside tools for detecting the impact of cannabis on driving abilities is critical given repeated studies reporting an increase in motor vehicle accidents and lethal accidents while driving under the influence of cannabis. This is particularly important given recent discussions regarding legalization of cannabis.
“To-date while there have been substantial developments regarding alcohol detection in recent years, we still have no accurate test for cannabis use and driving safety and this is a major concern we must address".