A Two‐Year Study of Δ 9 Tetrahydrocannabinol Concentrations in Drivers; Part 2: Physiological Signs on Drug Recognition Expert (DRE) and non‐DRE Examinations,, |
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| Authors: | Kari Declues M.S. Shelli Perez M.S. Ariana Figueroa M.S. |
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| Affiliation: | Orange County Crime Lab in Orange County, California, Santa Ana, CA |
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| Abstract: | Whole blood samples were examined for ?9‐Tetrahydrocannabinol (THC) over 2 years in drivers suspected of driving under the influence. Part one of the study examined the link between [THC] and performance on field sobriety tests. This portion examined objective signs, eye examinations and physiological indicators; and their relationship to the presence of THC. Several objective signs were excellent indicators of the presence of THC: red eyes (94%), droopy eyelids (85.6%), affected speech (87.6%), tongue coating (96.2%), and odor of marijuana (82.4%). About 63.6% of THC positive subjects had dialted pupils (room light). THC positive subjects had either rebound dilation or hippus in 88.8% of cases. Pulse and blood pressure (BP) were evaluated to determine any correlation with [THC]. An increased pulse rate correlated well to the presence of THC (88.5%), but not [THC]. BP did not correlate to [THC] and was also a poor indicator of THC in the blood (50% high). |
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| Keywords: | forensic science marijuana driving under the influence of drugs Drug Recognition Expert physiological signs dilated pupils rebound dilation |
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