Contents lists available at ScienceDirect International Journal of Drug Policy journal homepage: www.elsevier.com/locate/drugpo Research Paper The effect of Housing First on adherence to methadone maintenance treatment Milad Parpouchi ⁎ , Akm Moniruzzaman, Stefanie N. Rezansoff, Angela Russolillo, Julian M. Somers Somers Research Group, Faculty of Health Sciences, Simon Fraser University, Blusson Hall, Room 11300-8888 University Dr., Burnaby, British Columbia, V5A 1S6, Canada ARTICLE INFO Keywords: Methadone maintenance treatment Adherence Medication possession ratio Housing First Homelessness Mental illness ABSTRACT Background: Opioid overdose deaths have become a public health crisis in North America, and those who are homeless are particularly vulnerable. Methadone maintenance treatment (MMT) may prevent overdose and death among homeless people with opioid dependence, but suboptimal medication adherence is a common limitation. Previous research found that Housing First (HF) increases antipsychotic medication adherence among formerly homeless people. However, no experimental trials have examined whether HF has a significant impact on MMT adherence. We examined the intervention effect of HF on MMT adherence in a randomized sample of homeless adults experiencing mental illness and opioid dependence in Vancouver, Canada. Methods: Comprehensive administrative and self-reported data from homeless adults living with serious mental illness recruited to the Vancouver At Home study were analyzed. Only methadone recipients were included (n = 97). The medication possession ratio (MPR) was utilized as the measure of adherence, and relevant data were obtained from provincial administrative pharmacy records. Study arms were HF and treatment as usual (TAU). Student t-tests were used to test for differences in MMT MPR between HF and TAU. Results: No significant differences were observed in MMT MPR between participants in HF and TAU (0.52 vs. 0.57, p = 0.559) in the post-randomization period. Conclusion: HF was not associated with significantly different MMT MPR compared to TAU. Additional inter- ventions are indicated as HF alone was insufficient to facilitate improved MMT adherence among formerly homeless adults experiencing concurrent opioid dependence and serious mental illness. Introduction Opioid overdose deaths have increased and become a public health crisis in communities across North America (British Columbia Coroners Service, 2017; Rudd, Aleshire, Zibbell, & Gladden, 2016; Ruhm, 2017). Homeless people are at particular risk for nonfatal drug overdose (Fischer et al., 2004), and opioid overdose is reported as a major cause of death in this population (Baggett et al., 2013). Methadone main- tenance treatment (MMT) has been shown to reduce illicit opioid use (Gowing, Farrell, Bornemann, Sullivan, & Ali, 2011; Mattick, Breen, Kimber, & Davoli, 2009) and related mortality (Brugal et al., 2005; Caplehorn, Dalton, Haldar, Petrenas, & Nisbet, 1996; Huang et al., 2011; Langendam, van Brussel, Coutinho, & van Ameijden, 2001), al- though little research has examined the effectiveness of MMT among opioid-dependent homeless people. Inconsistent adherence to MMT can be problematic, as this can increase susceptibility to overdose (Wolff, 2002). Preliminary analysis of MMT adherence in a Canadian sample of homeless and mentally ill adults found that methadone was taken on fewer than half of the days over an average 6.5–year period after initiating treatment (Parpouchi, Moniruzzaman, Rezansoff, Russolillo, & Somers, 2017). A treatment schedule requiring MMT patients to visit a pharmacy daily for wit- nessed ingestion of methadone has been found to be difficult for some patients (Anstice, Strike, & Brands, 2009) and may hence pose barriers to consistent adherence. Illicit opioid use during treatment has also been found to be associated with poorer adherence (Raffa et al., 2007), and researchers have argued that doses should be titrated rapidly during induction to increase the proportion of people experiencing abstinence from illicit opioid use during MMT (Trafton, Minkel, Humphreys, 2006). However, it is important to note that the highest risk of overdose during MMT is during the induction phase (Baxter et al., 2013), and titrating doses too quickly can lead to respiratory https://doi.org/10.1016/j.drugpo.2018.03.012 Received 27 November 2017; Received in revised form 8 February 2018; Accepted 13 March 2018 ⁎ Corresponding author. E-mail addresses: spa16@sfu.ca (M. Parpouchi), akm_moniruzzaman@sfu.ca (A. Moniruzzaman), sra20@sfu.ca (S.N. Rezansoff), arussoli@sfu.ca (A. Russolillo), jsomers@sfu.ca (J.M. Somers). International Journal of Drug Policy 56 (2018) 73–80 0955-3959/ © 2018 Elsevier B.V. All rights reserved. T