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 detectedDetermine if DRE indicators for cannabis are present in cases with THC detected Compare indicators for subjects with active THC versus THC-COOH onlyCompare indicators for subjects with active THC versus THC-COOH only

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

DRE indicators for cannabis category Lack of convergence (LOC) presentLack of convergence (LOC) present Pupil size normal to dilatedPupil size normal to dilated Elevated pulse rateElevated pulse rate Elevated blood pressureElevated blood pressure Horizontal gaze nystagmus (HGN) not presentHorizontal gaze nystagmus (HGN) not present Vertical nystagmus (VGN) not presentVertical nystagmus (VGN) not present Reaction to light is normalReaction to light is normal Body temperature is normalBody temperature is normal

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

Methodology DRE cases from ; blood sample analyzedDRE cases from ; blood sample analyzed Tested for volatiles by Headspace Gas ChromatographyTested for volatiles by Headspace Gas Chromatography EMIT drug screenEMIT drug screen –Cannabinoids cut off = 10 ng/mL THC-COOH THC confirmation by GC/MS (SIM mode)THC confirmation by GC/MS (SIM mode) –Limits of Detection THC = 1.0 ng/mLTHC = 1.0 ng/mL THC-COOH = 5.0 ng/mLTHC-COOH = 5.0 ng/mL Cases that were only positive for THC or THC-COOH

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

147 THC/THC-COOH cases Mean = 74.1; median = 61.7 Mean = 7.3; median = THC-COOH only cases Mean = 16.6; median = 13.5Results

Lack of convergence *p=0.003

Normal range: 2.5 – 5.0 mm Average pupil size: Room light 56%, 61% above normal range

Average pupil size: Dark Normal range: mm 60%, 58% above normal range

Average pupil size: Direct light 49%, 47% above normal range Normal range: 2.0 – 4.5 mm

Average pulse Normal range = bpm 57% above normal range

Systolic blood pressure Normal range = 120 – 140 mm Hg 45% above normal range

Body Temperature Normal range = 98.6 ± 1°F 73, 87% in normal range

Not impaired: 17 cases from Summary Cannabis indicator THC/THC- COOH THC- COOH Not impaired HGNNone9%11%6% VGNNone02%0 Lack of convergencePresent66%47%6% PupilSizeNormal to dilated 55% 15% Reactionto lightNormal76%77%82% PulseElevated57% 25% Blood pressure (Systolic/diastolic) Elevated45%/22%45%/25%41%/12% Body TemperatureNormal73%87%77%

Summary THC/THC- COOH THC-COOH Bloodshoteyes Eyelidtremors 2/8 clues on WAT 2/4 clues on OLS Not impaired 86%81%24% 81% 38% 72%81%25% 46%57%31%

Other indicators Romberg test: estimation of 30 secondsRomberg test: estimation of 30 seconds –Normal range = 25 to 35 seconds THC/THC-COOHTHC-COOHNot impaired 60%51%47%

Other indicators Rebound DilationRebound Dilation Reaction to lightReaction to light –Normal, slow, little THC/THC-COOHTHC-COOHNot impaired 43%41%6% THC/THC-COOHTHC-COOHNot impaired 77%76%82%

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

Conclusions DRE matrix is useful tool for predicting marijuana useDRE matrix is useful tool for predicting marijuana use Similar indicators for THC/THC-COOH and THC-COOH casesSimilar 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)Examined which indicators best predict substance (n =742) Stimulants versus cannabisStimulants 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:

Acknowledgments Rod GullbergRod Gullberg –Research Analyst, Washington State Patrol