National Institute of Justice-supported researchers from RTI International recently published the results of their research showing that field sobriety tests and THC levels are unreliable indicators of marijuana intoxication.
The full study can be read here. A summary of the research is available here and provided the following take-aways that will be of interest for DWI attorneys:
- The researchers reported that the one leg stand, walk and turn, and modified Romberg balance tests were not sensitive to cannabis intoxication for any of the study participants.
- Results from the toxicology tests showed that the levels of all three targeted cannabis components (THC, cannabidiol, and cannabinol) in blood, urine, and oral fluid did not correlate with cognitive or psychomotor impairment measures for oral or vaporized cannabis administration.
- RTI concluded that, for their dosing study, THC levels in biofluid were not reliable indicators of marijuana intoxication.
- The researchers also observed that standardized field sobriety tests commonly used to detect driving under the influence of drugs or alcohol were not effective in detecting marijuana intoxication.
- However, it is important to note that many participants had low levels of THC in their blood and oral fluid at timepoints where they exhibited substantially decreased performance on cognitive and psychomotor assessments.
Source: National Institute of Justice, “Field Sobriety Tests and THC Levels Unreliable Indicators of Marijuana Intoxication,” April 5, 2021, nij.ojp.gov:
https://nij.ojp.gov/topics/
