Associations between methadone maintenance
treatment and crime: a 17-year longitudinal cohort study
of Canadian provincial offenders
Angela Russolillo , Akm Moniruzzaman, Lawrence C. McCandless, Michelle Patterson &
Julian M. Somers
Faculty of Health Sciences, Simon Fraser University, Burnaby, BC, Canada
To estimate and test the difference in rates of violent and non-violent crime during medicated and non-medicated
methadone treatment episodes.
Design, Setting and Participants
The study involved linkage of population level admin-
istrative data (health and justice) for all individuals (n = 14 530) in British Columbia, Canada with a history of conviction
and who ﬁlled a methadone prescription between 1 January 1998 and 31 March 2015. Methadone maintenance treat-
ment was the primary independent variable and was treated as a time-varying exposure. Each participant’s follow-up
(mean: 8 years) was divided into medicated (methadone was dispensed) and non-medicated (methadone was not dis-
pensed) periods with mean durations of 3.3 and 4.6 years, respectively.
Socio-demographics of partici-
pants were examined along with the main outcomes of violent and non-violent offences.
During the ﬁrst 2
years of treatment (≤ 2.0 years), periods in which methadone was dispensed were associated with a 33% lower rate of vi-
olent crime [0.67 adjusted hazard ratio (AHR), 95% conﬁdence intervals (CI) = 0.59, 0.76] and a 35% lower rate of non-
violent crime (0.65 AHR, 95% CI = 0.62, 0.69) compared with non-medicated periods. This equates to a risk difference of
3.6 (95% CI = 2.6, 4.4) and 37.2 (95% CI = 33.0, 40.4) fewer violent and non-violent offences per 100 person-years, re-
spectively. Signiﬁcant but smaller protective effects of dispensed methadone were observed across longer treatment inter-
vals (2.0 to ≤ 5.0 years, 5.0 to ≤ 10.0 years).
Among a cohort of Canadian offenders, rates of violent and
non-violent offending were lower during periods when individuals were dispensed methadone compared with periods in
which they were not dispensed methadone.
Keywords Crime, methadone, methadone maintenance treatment, MMT, offenders, substitution treatment.
Correspondence to: Angela Russolillo, Somers Research Group, Faculty of Health Sciences, Simon Fraser University, 8888 University Drive, Burnaby, BC V5A
1S6, Canada. E-mail: firstname.lastname@example.org
Submitted 17 May 2017; initial review completed 29 June 2017; ﬁnal version accepted 29 September 2017
Opioid dependence is one of the most common types of
illicit drug dependence globally , and has signiﬁcant
impacts upon public health and public order. Individuals
misusing opioids are associated with increased morbidity
and mortality [2,3] and have a strong, if varied, association
with crime and incarceration [4–6]. Methadone
maintenance treatment (MMT) remains one of the best-
researched and most-utilized opioid substitution treat-
ments (OST) for opioid dependence [7,8]. Clinical trials
have reported methadone as superior to other OSTs in
retaining individuals in treatment [9,10]. Individuals en-
gaged in MMT are associated with a range of positive
treatment outcomes, including reductions in criminal ac-
tivity [11,12]. Given the chronic nature of opioid depen-
dence, retention in treatment has been identiﬁed as an
important predictor of favorable treatment outcomes
, especially when examining offending risk. Besides
the well-documented associations between drug misuse
and crime , criminal histories including violent
offending and increased contact with custody are risk fac-
tors for poor OST treatment retention . The question
of how methadone inﬂuences criminal behavior is impor-
tant, given the elevated risk for crime among individuals
with regular and dependent heroin use , and the con-
sequence of criminal histories in preventing treatment ini-
tiation and adherence.
© 2017 Society for the Study of Addiction Addiction, 113,656–667