Transcript Impact of legalized recreational marijuana in Washington State

Impact of legalized recreational
marijuana in Washington State
Brianna Peterson, PhD, F-ABFT
Washington State Patrol
Toxicology Laboratory Division
History of marijuana in WA
• Medical marijuana legalized in 1998
• Removes state-level criminal penalties on the use,
possession and cultivation of marijuana by patients
who possess "valid documentation" from their
physician affirming that he or she suffers from a
debilitating condition and that the "potential
benefits of the medical use of marijuana would
likely outweigh the health risks."
• No established state registration program
WA State Initiative-502
• Public initiative; November 6, 2012 general ballot
• Approved by popular vote (~56%)
• Defined and legalized small amounts of marijuana and
marijuana-infused products
• Regulated marijuana production, distribution, and sale
• DUI laws amended to include a per se level for blood THC
• Possession by anyone <21 years, possession in larger
amounts, & unlicensed/unregulated production of marijuana
remains illegal
Driving Under the Influence (RCW 46.61.502/3)
• (1) A person is guilty of driving while under the influence …
(b) The person has, within two hours after driving, a THC concentration
of 5.00 or higher as shown by analysis of the person's blood … ; or
(c) While the person is under the influence of or affected by intoxicating
liquor, marijuana, or any drug;
• 4(b) Analyses of blood samples obtained more than two hours after the
alleged driving may be used as evidence that within two hours … a person
had a THC concentration of 5.00 or more … and … above 0.00 may be used
as evidence that a person was under the influence of or affected by
marijuana …
• (under 21 years): … has, within two hours … a THC concentration above
0.00
Toxicology testing in WA
• Only one toxicology lab for entire state
• Receive approximately 15,000 cases a year
• Case types: Death investigation, DUI, DRE, sexual assault
• 39 counties
• Testing is a free service funded by the state
Toxicology Testing
• All cases are tested for ethanol
• All cases are screened for the following drug/drug class(es):
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Amphetamines
Barbiturates
Benzodiazepines
Cannabinoids (cutoff for positive: carboxy THC at 10 ng/mL)
Cocaine metabolite
Methadone
Opiates
PCP
Tricyclic antidepressants
• Enzyme Multiplied Immunoassay Technique
THC Results
Year
Total # DUI/DRE
cases received
# of positive THC
cases
% of positive
THC cases
2009
4,809
877
18.2%
2010
5,012
974
19.4%
2011
5,132
1,036
20.2%
2012
5,298
988
18.6%
2013*
5,468
1,362
24.9%
2014
6,270
1,759
28.0%
2015
7,044
2,311
32.8%
2016 (Jan-April)
2,842
977
34.4%
Carboxy-THC Results
Year
Total # DUI/DRE
cases received
# of positive
Carboxy-THC
cases
% of positive
Carboxy-THC
cases
2009
4,809
1,267
26.3%
2010
5,012
1,413
28.2%
2011
5,132
1,460
28.4%
2012
5,298
1,515
28.6%
2013*
5,468
2,187
40.0%
2014
6,270
2,279
36.3%
2015
7,044
2,693
38.2%
2016 (Jan-April)
2,842
1,108
39.0%
Marijuana-related driving cases (%)
45.0%
40.0%
35.0%
30.0%
25.0%
Carboxy-THC
20.0%
THC
15.0%
10.0%
5.0%
0.0%
2009 2010 2011 2012 2013 2014 2015 2016
Demographics of marijuana positive
cases
Year
Percent Male
Age, Range
Age, Median
2009
80 %
14 - 76 years
25 years
2010
78 %
15 - 74 years
25 years
2011
2012
2013
2014
2015
81 %
77 %
79 %
80 %
81 %
14 - 70 years
16 - 85 years
14 - 78 years
15 – 74 years
13 – 73 years
25 years
25 years
26 years
26 years
27 years
Summary of THC blood concentrations
Year
# cases positive
for THC
THC
concentration
range
Average THC
concentration
Median THC
concentration
2011
1,036
1-58 ng/mL
6.4 ng/mL
4.8 ng/mL
2012
988
1-90 ng/mL
8.0 ng/mL
6.2 ng/mL
2013
1,362
2-77 ng/mL
7.2 ng/mL
5.2 ng/mL
2014
1,759
1-100 ng/mL
6.1 ng/mL
3.9 ng/mL
2015
2,311
1-69 ng/mL
5.7 ng/mL
3.8 ng/mL
2016 (JanApril)
977
1-66 ng/mL
5.8 ng/mL
3.7 ng/mL
THC cases at or above 5 ng/mL
Year
# cases positive
for THC
# cases positive for
THC below 5 ng/mL
# cases (%) positive
for THC above 5
ng/mL
2011
1,036
530
506 (49%)
2012
988
378
610 (62%)
2013
1,362
642
720 (53%)
2014
1,759
1,056
703 (40%)
2015
2,311
1,389
922 (40%)
2016 (JanApril)
977
593
384 (39%)
Beyond the tox
results
Missouri v. McNeely
• 2013 US Supreme Court decision
• “Police must generally obtain a warrant before subjecting a
drunken-driving suspect to a blood test”
Prosecutor’s perspective
• Affected by cases easier to prove before I-502 passed
• Since implementation things have gotten more difficult:
• Under 5 ng/mL cases, prosecutors must review police video
• Over 5 ng/mL cases usually involve more impairment so it is
easier to charge on the affected by prong
• Many DUI’s are dealt when under the per se level even with
good signs of impairment and poor field sobriety tests
• Exigent circumstances cases are usually thrown out
• Increased ethanol and marijuana combined driving cases
Internal procedural changes
• Normalize data in an attempt to eliminate effect of changes
• Reporting limits
• THC: changed from 1 to 2 ng/mL
• Carboxy-THC: changed from 5 to 10 ng/mL
• 2009-2012, often no EMIT/drug screen if blood alcohol > 0.10%
• Exceptions: vehicular assault/homicide, drug specifically mentioned or
requested, circumstances suggest drug use, DRE cases
Percentage of cases (BAC >0.10%) with EMIT
positive results, Jan-Apr 2008, N=548
Opiates
6%
Benzo's
7%
Cocaine met.
3%
Cannabinoids
Benzodiazepines
Opiates
Cocaine Met.
Barbiturates
Cannabinoids
22%
Methadone
CNS Drugs Neg
60%
Amphetamines
Tricyclic ADs
Propoxyphene
Phencyclidine
Data interpretation
• Reliable information regarding traffic accidents and traffic
deaths to correlate with toxicology results
• Information regarding time course of incident: time of stop and
time of blood draw.
• THC has a short half life
• Uncertainty of Measurement
• 26% for THC at k=3 (99.7% confidence)
• Result of 6.7 ng/mL is reported at 6.7 ± 1.7 ng/mL
Things to remember
• Establish a reliable baseline of data
• Benefit of having years of comparison data
• Be aware of any changes in testing practices
• Lower limit of reporting
• Increasing number of cases tested
• Be aware of what is scope of data
• Regional – different labs testing, different reporting guidelines,
different uncertainty measurements
• Are all cases being screened for marijuana use?
Questions?
[email protected]
206-262-6100