May 4, 2024

Driving High: Can Field Sobriety Tests Identify Drivers Under the Influence of Cannabis?

Field Sobriety Tests and Cannabis Impairment
In a research study released August 2, 2023, in JAMA Psychiatry, scientists at the University of California San Diego Center for Medicinal Cannabis Research performed a double-blind, placebo-controlled randomized scientific trial to assess how accurate field sobriety tests are in determining chauffeurs under the influence of THC. The outcomes revealed that tests administered by police officers could distinguish in between individuals who had consumed THC versus those who had not at certain time points. Still, the general precision of the tests may be inadequate to signify THC impairment on their own.
Cannabis is the illicit drug most frequently discovered in the blood of chauffeurs associated with motor automobile crashes, including deadly ones.
” Driving is a complicated job that requires undamaged attention and motor skills to stay safe,” stated very first author Thomas Marcotte, PhD, teacher of psychiatry at UC San Diego School of Medicine and co-director of the Center for Medicinal Cannabis Research at UC San Diego. “While marijuana can be impairing, the impacts vary for each individual. There is therefore a public health need to confirm that examinations of problems are objective and efficient, and this research study is an essential step towards that goal.”
Study Methodology and Results
The research study consisted of 184 adult marijuana users aged in between 21 and 55. During the experiment, 63 participants were given a placebo cannabis cigarette, while 121 individuals received a THC marijuana cigarette. Participants who took in the THC reported an average highness level of 64 on a scale of 0 to 100, suggesting considerable intoxication was achieved.
Highly experienced law enforcement officers then carried out field sobriety tests to examine capabilities such as balance, coordination, divided attention, and eye motions. These include the Walk and Turn, One Leg Stand, Finger to Nose, Lack of Convergence, and Modified Romberg tests. The tests were carried out at 4 various time periods, approximately one, 2, 3, and four hours after cigarette smoking.
The outcomes showed that officers categorized a substantially higher proportion of individuals in the THC group as being impaired based upon the field sobriety tests compared to the placebo group at three of the 4 time points measured. For instance, one hour after cigarette smoking, they identified 98 participants (81%) from the THC group as being impaired based upon their efficiency, and 31 participants (49%) from the placebo group. Regardless of their actual project (THC vs. placebo), officers thought that 99% of those who stopped working the tests had consumed THC.
Driving Simulation and Field Sobriety Tests
In addition to the field sobriety tests, study participants undertook a driving simulation, which was discovered to significantly associate with the outcomes of chosen field sobriety tests. However, officers were not privy to this information.
The researchers concluded that existing field sobriety tests may be sensitive enough to find those under the impact of marijuana. The substantial overlap in bad test performance in between the placebo and THC groups, and the high frequency at which officers presumed this was since of THC usage, suggest that field sobriety tests alone may be inadequate to determine THC-specific driving problems.
Future Implications and Research
The authors keep in mind that officers in the field would be geared up with more information by speaking with the chauffeur and observing their driving ability, so combining the field sobriety tests with this extra info might show more successful in a general determination of whether a chauffeur suffers.
” Field sobriety tests are helpful additions to total examinations of chauffeurs, but are not accurate enough by themselves to identify THC impairment,” stated Marcotte. “New reliable measures for identifying marijuana problems are required to make sure the safety of all drivers on the roadway.”
The UC San Diego Center for Medicinal Cannabis Research has now partnered with the California Department of Motor Vehicles and the California Highway Patrol on a follow-up study to test numerous techniques of spotting cannabis-impaired driving. The research study aims to hire 300 individuals and is set to begin in late summer 2023.
Referral: “Evaluation of Field Sobriety Tests for Identifying Drivers Under the Influence of CannabisA Randomized Clinical Trial” by Thomas D. Marcotte, PhD; Anya Umlauf, MS; David J. Grelotti, MD; Emily G. Sones, BA; Kyle F. Mastropietro, BS; Raymond T. Suhandynata, PhD; Marilyn A. Huestis, PhD; Igor Grant, MD and Robert L. Fitzgerald, PhD, 2 August 2023, JAMA Psychiatry.DOI: 10.1001/ jamapsychiatry.2023.2345.
Co-authors include: David J. Grelotti, Kyle F. Mastropietro, Raymond Theodore Suhandynata, Igor Grant, Anya Umlauf, Emily G. Sones and Robert L. Fitzgerald, all at UC San Diego, as well as Marilyn A. Huestis at Thomas Jefferson University.
The research study was moneyed by the State of California by means of Assembly Bill 266, contract 907.

A study from the University of California San Diego assessed the effectiveness of field sobriety tests in identifying THC-induced driving problems. The outcomes recommended that while these tests can distinguish in between THC customers and non-consumers at certain time points, they might not be adequate in definitively determining THC-specific driving impairment.
UC San Diego scientists examine how precise law-enforcement administered field sobriety tests are at determining cannabis direct exposure and problems.
In an age of increasing marijuana legalization, road safety is a crucial concern. Marijuana is known to hinder reaction time, coordination, decision-making, and understanding– skills necessary for safe driving. In the last 3 years, California has actually seen a 62% increase in the variety of deadly crashes including drug-related problems.
Challenges in Measuring THC Impairment
Remarkably, the correlation in between blood alcohol concentrations and problems is not mirrored in tetrahydrocannabinol (THC) blood concentrations and driving efficiency. Police officers must instead depend upon behavioral tests to assess a motorists level of impairment. These field sobriety tests were mostly validated based on alcohol usage, so their efficiency in spotting cannabis disability stays unsure.

In a research study published August 2, 2023, in JAMA Psychiatry, scientists at the University of California San Diego Center for Medicinal Cannabis Research carried out a double-blind, placebo-controlled randomized scientific trial to assess how accurate field sobriety tests are in determining motorists under the impact of THC. Still, the general accuracy of the tests may be insufficient to denote THC impairment on their own.
Highly experienced law enforcement officers then carried out field sobriety tests to analyze abilities such as balance, coordination, divided attention, and eye motions. The results showed that officers categorized a considerably higher percentage of participants in the THC group as being impaired based on the field sobriety tests compared to the placebo group at 3 of the four time points determined.

These field sobriety tests were primarily verified based on alcohol intake, so their effectiveness in detecting marijuana impairment remains unsure.