Trends in Detection Rates of
Risky Marijuana Use in CO
Healthcare Settings
Acknowledgements
» SBIRT Colorado is a statewide initiative of
the Office of the Governor, funded by
SAMHSA, administered by DBH, managed
by Peer Assistance Services
» Authors: Melissa Richmond, Katie Page,
Laura Rivera, Brie Reimann, Leigh Fischer
» Thanks to: DBH, Peer Assistance, SBIRT
team, Dr. Fred Pampel
Introduction
» Marijuana Use and Abuse
» 17.4 million users nationwide (2010 NSDUH)
» 32% increase in marijuana treatment
admissions 1996-2006 (2009 TEDS)
» 9% of all users and 25-50% of daily users
become dependent (NIDA)
» Other consequences
Marijuana Policy
» National Marijuana Policy
» 16 states have legalized medical marijuana
» States with medical marijuana laws have
higher rates of marijuana use
» Colorado Marijuana Policy
» Legalized medical marijuana in 2000
» Rapid growth of marijuana industry since
2009
» Uses a dispensary system requiring physician
approved medical marijuana cards
Implications of Legislative
Changes
» Substance use prevention research:
» Availability, price, advertisement, social norms
» Implications for healthcare providers
» Opportunities to use data from prevention
and treatment programs to assess
changes
» Colorado SBIRT
SBIRT Model
Specific Aims
1. Examine trends in rates of patients
screening positive in healthcare settings
for risk-prone patterns of marijuana use in
CO
2. Assess trends in severity of use at time of
screening among marijuana users
3. Examine if trends in use or severity of
use differ by age and gender
Methods
» Participants
» 108,907 patients were screened in 12
healthcare sites (Jan 2008 – August 2011)
» Mean age 44.2 years (SD 17.7; range 18-85)
» 53% Female
» 59% identified as White, 28.4% as Hispanic, &
8.7% as Black
SBIRT Colorado
Methods
» Procedures & Measures
1. Brief screen questions (tobacco, alcohol,
drug use)
2. Health Educator administered ASSIST
(WHO)
»
»
»
Prior use and negative consequences “During
the past 3 months, how often has your use of
cannabis lead to health, social, legal, or financial
problems”
Scored 0-39
4+ on cannabis scale = at least moderate risk
3. Any medical marijuana use = ASSIST
Results
» 8,748 (8%) patients screened positive for
marijuana
» Odds of screening positive accelerating in
early 2009 (interaction with patient age)
Probability of a positive screen
FIGURE 1. Results of logistic regression analyses predicting
probability of positive marijuana screen (4+ ASSIST).
0.30
0.25
0.20
0.15
0.10
0.05
0.00
27yr Male
27yr Female
61yr Male
61yr Female
Probability of a positive screen
FIGURE 2. Results of logistic regression analyses predicting
probability of positive marijuana screen (11+ ASSIST)
0.30
0.25
0.20
0.15
0.10
0.05
0.00
27yr Male
27yr Female
61yr Male
61yr Female
Results
» Odds of screening positive increased over
time (nonlinear)
» Odds of a positive screen were 60% lower
for females than for males
» Controlling for time and gender, for every
10 years older patients were, odds of a
positive screen decreased by 38-40%
Results
» Severity of Use Among Users (1+ on the
ASSIST)
» Linear increase over time
» Less severe use with age
» Less severe use for females than males
» 1.6% of the variance in severity was
explained by the model
Discussion
» Increases in positive marijuana screens over
time correspond to changing landscape
» Consistent results across 2 scoring methods
» Probability of positive screen increased over time for
all individuals
» Young males had highest probability of positive
screen
» Older adults
» Greater proportional increases at low threshold (4+
Assist)
Discussion
» Severity of use
» Severity of use increased over time
» Males > Females
» Younger > Older
» Consistent with national trends
» Majority of national treatment admissions are for
males & individuals < age 30
Discussion
» Healthcare providers likely serving increasing
numbers of patients using marijuana
» < 5% of CO physicians authorize medical marijuana
» Lack of rigorous regulations around manufacture,
distribution and dosage
» Universal screening: opportunity to intervene
Limitations
» Rapid change in marijuana landscape
» Multiple factors likely impact increased
marijuana use
» SBIRT 2 phase screening process may have
missed marijuana users
» Generalizability
Future Directions
» Further research on best practices for
healthcare providers
» Universal screening protocols as a way to
address risk-prone use
» Continued changes to marijuana policy
Richmond, M.K., Page, K., Rivera, L.S.,
Reimann, B., & Fischer, L. (in press). Trends
in Detection Rates of Risky Marijuana Use in
Colorado Healthcare Settings. Substance
Abuse.
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