Barry K Logan

Chief of Forensic Toxicology

NMS Labs

Willow Grove PA

Marijuana and its Effects on Driving

Medical Versus Recreational Cannabis

• Typical Recreational Doses (Ramaekers)

• 200-300ug/Kg THC

• ~14-21mg THC in a 150lb person

• ~0.1 - 0.2g 10% THC plant material

• Medical dosing guidelines (Aggarwal, Kahan)

• Federal Single Patient Dosage 8.24g/day

• ~0.2g THC/dose QID (Aggarwal)

• ~0.02g THC/dose QID (Kahan)

Cannabinoid Effects

Cannabinoid Pharmacology

• Cannabis used >4000 yrs for

euphoric & therapeutic effects

• Marijuana, hashish, sinsemilla

• >500 chemicals & at least 109

cannabinoids:

• THC (major psychoactive component)

• cannabinol (10% as psychoactive as THC)

• cannabidiol (non-psychoactive)

• Ratios of cannabinoids & potency vary

based on age, geographical origin, genus

& method of cultivation (hydroponics) M Huestis

The CB-1 Receptor

Creative Commons

CerebellumMovement

Basal GangliaMovement Cerebral Cortex

Higher cognitive function

HippocampusLearning. Memory, stress

Spinal cordPeripheral sensation/pain

HypothalamusAppetite

MedullaNausea/vomiting, CTZ

Cannabinoid Pharmacology

Acute Physiological Effects

• Rapid Heart Rate

• Bloodshot Eyes

• Dry Mouth

• Increased appetite

• Decreased respiratory rate

• Analgesia

• Vasodilation

• Bronchodilation

Cannabinoid Pharmacology

Acute Psychoactive Effects

• Euphoria

• Relaxation/Stress Reduction

• Enhanced Perception

• Music, Humor, Arts

• Increased Creativity/Abstract Thinking/Sensuality

• Illusions/Pseudohallucinations

• Time Distortion

• Ataxia

• Anxiety, Paranoia, Illusions, Depersonalization

Cannabis and Impairment

Acute Cognitive Effects:

�Concentration and sustained attention/vigilance.

�Fatigue, sleepiness, lethargy, memory problems.

�Reaction time

�Difficulty in thinking and

problem-solving.

�Difficulty in registering,

processing, and using

information.

Cannabis and Impairment

Psychomotor Aspects

�Decreased motor coordination

�Slurred speech

�Dizziness

�Impairment in reaction time

and tracking.

Cannabis and Driving

Driving Deficits

�Attention

�Vigilance

�Arousal

�Weaving

� Impulsivity

�Reaction Time

Cannabis and Driving

• Experimental Evidence• THC’s impairing effects increase with task complexity.

• Unexpected circumstances and choice during otherwise

monotonous driving cause increased risk for errors over

non-cannabis using controls.

• Reaction time, road tracking, weaving, steering wheel

variability, and brake latency all increase with recent

cannabis exposure.

• THC effects on cognitive performance following smoking

include immediate recall, executive functioning, working

memory and attention.

• Crash risk results are mixed

Hartman RL, Huestis MA. Cannabis effects on driving skills. Clin Chem. 2013 Mar;59(3):478-92.

Cannabinoid Pharmacokinetics

Route of Administration

• Products:

• Plant material

• Hashish

• Concentrates: Oil/BHO/Glass Shatter

• Route:

• Cigarettes/Joints/Blunts

• Smoking/Vaping – Pens, Volcano, etc

• Oral – Capsules, Syringes, Baked Goods, candy, etc

Smoked/Vaped Cannabis

Smoked THC Time-Concentration Curve

Courtesy Marilyn Huestis, Borkenstein Drug Course, 2012

• THC Concentrations peak within minutes of last inhalation, and fall rapidly as the drug distributes.

Factors Affecting Peak/Concentration

• Smoked Dose

• Potency of marijuana

• Amount smoked

• Duration and frequency of smoking/inhalation

• Depth of inhalation/breath holding

• Body Fat

• Co-ingestion with alcohol or other drugs

• Time between smoking and blood draw

Smoked/Vaped Cannabis

Smoked THC Time-Concentration Curve

Courtesy Marilyn Huestis, Borkenstein Drug Course, 2012

• There is substantial inter-subject variability in peak THC concentration based on smoking technique, body fat, metabolism

Smoked/Vaped Cannabis

Visual Analog Scale Composite Stoned, High, Strength (n=63)

Smoked/Vaped Cannabis

Feel-Drug Visual Analog Scale

Oral Cannabis

• Products are not

accurately

labeled for dose

• No ability to

titrate dose

• THC

concentrations

peak at 4-5 hours

• Blood THC levels

are extremely

low, while

impairment is

severe

Cone E, NSC Congress, Atlanta, 2015

THC in DUID

Cannabis and Driving

Driving Deficits

�Attention

�Vigilance

�Arousal

�Weaving

� Impulsivity

�Reaction Time

Cannabinoid Concentrations

• There is no good evidence linking specific THC

thresholds in blood to a degree of impairment

• Studies that have established effect thresholds collect

blood samples during driving or from fatally injured drivers.

• Enforcement blood samples are typically collected

45 minutes to 2 hours after alleged impaired driving.

• THC concentrations change dramatically over 30 minutes,

and can’t reliably be extrapolated to the time of driving.

• Blood concentrations do not approximate the

concentrations in the brain, especially after oral ingestion

• A threshold of 1, 2, or 5ng/mL at the time of test is not

evidence of impairment at the time of driving

Real World Cannabinoid Concentrations

Driving

Smoking

40

30

20

10

Arrested

Tested

Current Per Se Laws for Cannabis

StateStateStateState ThresholdThresholdThresholdThreshold Year PassedYear PassedYear PassedYear Passed

AZ ZT, incl mets 1990

COCOCOCO 5ng/mL5ng/mL5ng/mL5ng/mL, THC (permissible inf.) 2012

DE ZT, excl mets 2007

IL ZT, incl mets 1997

IN ZT, incl mets 2001

IA Urine per se 1998

MI ZT, excl mets 2003

MTMTMTMT 5ng/mL 5ng/mL 5ng/mL 5ng/mL THC 2013

NVNVNVNV 2ng/mL2ng/mL2ng/mL2ng/mL THC, mets 2003

NC ZT, U21, excl mets. 2003

OHOHOHOH 2ng/mL2ng/mL2ng/mL2ng/mL THC, mets 2006

OK ZT, incl mets 2013

PAPAPAPA 1ng/mL1ng/mL1ng/mL1ng/mL, incl mets 2004

RI ZT, incl mets 2006

SD ZT, U21, incl mets 1998

UT ZT, incl mets 1994

WAWAWAWA 5ng/mL 5ng/mL 5ng/mL 5ng/mL THC 2012

WI ZT, excl mets. 2003

*ZT: Zero tolerance means any

detectable amount or amount

established based on laboratory

protocol.

2014: 17 states have per se

StateStateStateState ThresholdThresholdThresholdThreshold

WA, CO, MT 5ng/mL

NV, OH 2ng/mL

PA 1ng/mL

Current Per Se Laws for Cannabis

StateStateStateState ThresholdThresholdThresholdThreshold Year PassedYear PassedYear PassedYear Passed

AZ ZT, incl mets 1990

COCOCOCO 5ng/mL5ng/mL5ng/mL5ng/mL, THC (permissible inf.) 2012

DE ZT, excl mets 2007

IL ZT, incl mets 1997

IN ZT, incl mets 2001

IA Urine per se 1998

MI ZT, excl mets 2003

MTMTMTMT 5ng/mL 5ng/mL 5ng/mL 5ng/mL THC 2013

NVNVNVNV 2ng/mL2ng/mL2ng/mL2ng/mL THC, mets 2003

NC ZT, U21, excl mets. 2003

OHOHOHOH 2ng/mL2ng/mL2ng/mL2ng/mL THC, mets 2006

OK ZT, incl mets 2013

PAPAPAPA 1ng/mL1ng/mL1ng/mL1ng/mL, incl mets 2004

RI ZT, incl mets 2006

SD ZT, U21, incl mets 1998

UT ZT, incl mets 1994

WAWAWAWA 5ng/mL 5ng/mL 5ng/mL 5ng/mL THC 2012

WI ZT, excl mets. 2003

*ZT: Zero tolerance means any

detectable amount or amount

established based on laboratory

protocol.

2015: 18 states have per se

StateStateStateState ThresholdThresholdThresholdThreshold

WA, CO, MT 5ng/mL

NV, OH 2ng/mL

PA 1ng/mL

IL (prop.) 15ng/mL

Cannabinoid Concentrations

% Subjects with

THC >1ng/mL

% Subjects with

THC >2ng/mL

% Subjects with

THC >5ng/mL

+ Cannabinoid

- Alcohol

- Other Drug

90.51% 78.9% 49.3%

+ Cannabinoid

+ Alcohol

- Other Drug

79.4% 56.8% 23.5%

Percentage of arrested drivers (n=4,799) with THC concentrations above various

statutory thresholds (1ng/mL(PA); 2ng/mL (OH, NV); 5ng/mL (WA, CO, MT).

Logan, Kacinko, Beirness, AAAFTS in press, 2015

Impact of 5ng/mL THC per se Law

0.00%

5.00%

10.00%

15.00%

20.00%

25.00%

0 5 10 15

[THC]blood, ng/mL[THC]blood, ng/mL[THC]blood, ng/mL[THC]blood, ng/mL

Relative Frequency %

10,144 Marijuana DUID /DRE cases testing positive for THC and/or metab.

Per Se / Zero Tolerance Pro’s and Con’s

ProProProPro ConConConCon

Raises the profile of the DUID

Issue

Based on policy, not science, but

carries an aura of scientific

authority

Creates a “black and white”

standard

Not an impairment standard

Useful tool for cases where

injuries prevent collection of

impairment evidence.

Drug users cannot be expected

to know what their blood

concentrations are.

Expedites litigation Setting a high concentration

renders the law useless; setting

a low concentration risks

including non-impaired subjects

Impact of Medical Cannabis Laws

Medical Cannabis in Canada

• “Cannabis users should be advised not to drive for at least 3 to 4 hours after smoking, for at least 6 hours after oral ingestion, and for at least 8 hours if they experience a subjective "high" (level II evidence)”.

Kahan M, Srivastava A, Spithoff S, Bromley L.

Prescribing smoked cannabis for chronic noncancer pain:

preliminary recommendations. Can Fam Physician. 2014

Dec;60(12):1083-90.

Medical Cannabis in Germany

• In summary, a low risk profile is evident from the literature available.

• However “Cannabinoids impede cognitive and psychomotor performance, resulting in impaired driving ability”.

Radbruch L, Nauck F. A review of side effects and

complications with cannabinoid treatment . Schmerz. 2003

Aug;17(4):274-9.

NORML Position

Medical Cannabis in Colorado

• “In Colorado, since mid-2009 when medical marijuana became commercially available and prevalent, the trend became positive in the proportion of drivers in a fatal motor vehicle crash who were marijuana-positive.”

• No significant changes were seen in 34 NMMS. • For both Colorado and NMMS, no significant changes

were seen in the proportion of drivers in a fatal motor vehicle crash who were alcohol-impaired.

Salomonsen-Sautel S, Min SJ, Sakai JT, Thurstone C, Hopfer C.

Trends in fatal motor vehicle crashes before and after

marijuana commercialization in Colorado. Drug Alcohol

Depend. 2014 Jul 1;140:137-44.

Cannabis Positive Traffic Deaths, CO

Salomonsen-Sautel et al, 2014

2009

Questionsbarry.logan@nmslabs.com