Evaluation of Drug Recognition Expert Reports in Marijuana

Evaluation of Drug Recognition Expert Reports in Marijuana Cases Brianna Peterson, Ph. D. and Rod Gullberg, M. S. Washington State Patrol September 20, 2011

Goal of study • Determine if DRE indicators for cannabis are present in cases with THC detected • Compare indicators for subjects with active THC versus THC-COOH only

DRE Matrix Depressants Inhalants Dissociative Anesthetics Cannabis Stimulants Hallucinogens Narcotic Analgesics Horizontal Gaze Nystagmus Vertical Gaze Nystagmus Present Present None None Lack of Convergence Present None Normal Dilated Constricted Slow Normal Little to none Down Up Up Up Down Up/Down Up Up Down Normal Up/Down /Normal Up Up Down Pupil size Reaction to light Pulse Blood Pressure Body Temp

DRE indicators for cannabis category • • Lack of convergence (LOC) present Pupil size normal to dilated Elevated pulse rate Elevated blood pressure • • Horizontal gaze nystagmus (HGN) not present Vertical nystagmus (VGN) not present Reaction to light is normal Body temperature is normal

THC pharmacokinetics • Highly lipid soluble • Short half-life – 3 hrs post smoking, THC in serum <5 ng/m. L • Main metabolite: 11 -nor-9 carboxy-THC (THC-COOH)

Methodology • DRE cases from 2007 -2009; blood sample analyzed • Tested for volatiles by Headspace Gas Chromatography • EMIT drug screen – Cannabinoids cut off = 10 ng/m. L THC-COOH • THC confirmation by GC/MS (SIM mode) – Limits of Detection • THC = 1. 0 ng/m. L • THC-COOH = 5. 0 ng/m. L Cases that were only positive for THC-COOH

Subjects • THC/THC-COOH (n=101) – – – 93% male 78% Caucasian Average age: 24 (range: 16 -70) • THC-COOH only (n=147) – – – 79% male 84% Caucasian Average age: 27 (range: 14 -61) • Not impaired (n=17) – – – 76% male 94% caucasian Average age: 38 (range: 19 -74)

Results 147 THC/THC-COOH cases THC-COOH concentration Mean = 7. 3; median = 5. 7 e or 21 0 M 18 0 15 0 30 More 12 0 20 90 10 60 5 ng/m. L Mean = 74. 1; median = 61. 7 101 THC-COOH only cases THC-COOH concentration 21 0 M or e 0 18 0 15 0 12 90 30 20 15 10 5 35 30 25 20 15 10 5 0 60 4 30 3 20 2 15 1 10 50 40 30 20 10 0 5 Frequency 60 50 40 30 20 10 0 Frequency THC concentration ng/m. L Mean = 16. 6; median = 13. 5

Lack of convergence 70 * 60 Percentage 50 40 Yes No 30 20 10 0 THC/THC-COOH *p=0. 003

Average pupil size: Room light Normal range: 2. 5 – 5. 0 mm 10 9 8 7 6 THC/THC-COOH 5 THC-COOH 4 56%, 61% above normal range 3 2 1 0 0 10 20 30 40 50 ng/m. L 60 70 80 90

Average pupil size: Dark Normal range: 5. 0 - 8. 5 mm 10 9 8 7 60%, 58% above normal range 6 THC/THC-COOH 5 THC-COOH 4 3 2 1 0 0 10 20 30 40 50 ng/m. L 60 70 80 90

Average pupil size: Direct light Normal range: 2. 0 – 4. 5 mm 10 9 8 7 6 5 THC/THC-COOH 4 THC-COOH 3 49%, 47% above normal range 2 1 0 0 10 20 30 40 50 ng/m. L 60 70 80 90

Average pulse Normal range = 60 -90 bpm 150 140 130 120 110 100 THC/THC-COOH 90 80 THC-COOH 57% above normal range 70 60 50 40 0 10 20 30 40 ng/m. L 50 60 70 80

Systolic blood pressure Normal range = 120 – 140 mm Hg 200 190 180 170 160 150 140 THC/THC-COOH 130 THC-COOH 45% above normal range 120 110 100 90 80 0 10 20 30 40 ng/m. L 50 60 70 80

Body Temperature Normal range = 98. 6 ± 1°F 101 100. 6 100. 2 99. 8 99. 4 73, 87% in normal range 99 98. 6 98. 2 97. 8 THC/THC-COOH 97. 4 THC-COOH 97 96. 6 96. 2 95. 8 95. 4 95 0 10 20 30 40 ng/m. L 50 60 70 80

Summary Cannabis indicator THC/THCCOOH Not impaired HGN None 9% 11% 6% VGN None 0 2% 0 Present 66% 47% 6% Normal to dilated 55% 15% Normal 76% 77% 82% Pulse Elevated 57% 25% Blood pressure Elevated 45%/22% 45%/25% 41%/12% Normal 73% 87% 77% Lack of convergence Pupil Size Reaction to light (Systolic/diastolic) Body Temperature Not impaired: 17 cases from 2007 - 2009

Summary THC/THCCOOH THC-COOH Not impaired Bloodshot eyes 86% 81% 24% Eyelid tremors 81% 38% 2/8 clues on WAT 72% 81% 25% 2/4 clues on OLS 46% 57% 31%

Other indicators • Romberg test: estimation of 30 seconds – Normal range = 25 to 35 seconds THC/THC-COOH Not impaired 60% 51% 47%

Other indicators • Rebound Dilation THC/THC-COOH Not impaired 43% 41% 6% • Reaction to light – Normal, slow, little THC/THC-COOH Not impaired 77% 76% 82%

DRE Opinion • THC/THC-COOH cases – 97% DRE called cannabis • Other cases called ‘not impaired’ – 98% subject admitted to marijuana use • THC-COOH only cases – 97% DRE called cannabis • Stimulant/not impaired – 88% subject admitted to marijuana use

Conclusions • DRE matrix is useful tool for predicting marijuana use • Similar indicators for THC/THC-COOH and THC-COOH cases – Short half-life, long exam process

Beasley et al. study • Examined which indicators best predict substance (n =742) • Stimulants versus cannabis – Stimulants: less reddening of eyes and rebound dilation, more likely to have hippus, injection sites, slow reaction to light – Cannabis: more likely to have lack of convergence Toward a More Parsimonious Approach to Drug Recognition Expert Evaluations. Traffic Injury Prevention 2009; 10: 513 -518

Acknowledgments • Rod Gullberg – Research Analyst, Washington State Patrol