Dynamics in the costs of criminality among opioid dependent individuals

Abstract

Background: Research into the avoided crime-related costs associated with methadone maintenance treatment (MMT) is sparse. Our objective was to characterize the dynamics in crime-related costs associated with MMT effectiveness among opioid dependent individuals in Vancouver, Canada.

Methods: We considered individuals enrolled in a prospective study between December, 2011 and May, 2013. Monthly crime-related costs (2013 CAD) were derived from self-reported criminal activity. On the basis of MMT receipt and illicit opioid use, individuals were classified in mutually exclusive health states: (i) MMT high effectiveness; (ii) MMT low effectiveness; (iii) opioid abstinence; or (iv) relapse. We classified individuals as daily, non-daily or non-stimulant users and controlled for demographic and socio-economic characteristics. A two-part multiple regression model was constructed; the first part modeled non-zero cost probability, the second estimated the level of costs. Avoided costs were estimated for each health state and stratified by stimulant use intensity.

Results: Our study included 982 individuals (median age 47, 38% female) for 2232 observations. Individuals on MMT with high effectiveness incurred lower monthly costs of criminality (avoided costs of $6298; 95% C.I. ($1578, $11,017)), as did opioid abstinent individuals ($6563 ($1564, $11,561)). Avoided costs for daily stimulant users were greater than for non-daily users, both for individuals on MMT with high effectiveness ($12,975 vs. $4125) and opioid abstinent ($12,640 vs. $4814).

Conclusion: Using longitudinal data on individuals with a history of MMT, we found substantially lower costs of criminality associated with high effect to MMT. Avoided costs were highest among daily stimulant users that were on MMT with high effectiveness or those opioid abstinent.

Keywords: Costs of criminality; Methadone maintenance treatment; Opioid use; Relapse; Stimulant use; Treatment outcomes.

Fig. 1

Observed health states at time of follow-up assessment for the 982 individuals included in our study, as well as the prevalence of drug use in each respective health state. Mutually exclusive health states are: (i) MMT with high effectiveness (current MMT receipt and no illicit opioid use in the last six months); (ii) MMT with low effectiveness (defined as current MMT receipt with illicit opioid use in the last six months); (iii) opioid abstinence (defined as no current MMT receipt and no illicit opioid use in the last six months); or (iv) relapse (defined as no current MMT receipt with illicit opioid use in the last six months). †Drugs considered for polydrug use categorization were hard drugs only, defined for our purposes as heroin, crack, cocaine, crystal methamphetamine or combination of. ‡ Heavy alcohol use is defined as consuming more than 4 drinks each day.

Fig. 2

Monthly crime-related costs (top panel), monthly avoided costs when compared to relapse (middle panel) and monthly avoided cost percentages when compared to relapse (bottom panel) were estimated from average marginal effects (AME) derived from a two-part multiple regression model. Results presented are for each mutually exclusive health state for all individuals (2232 observations) as well as stratified by stimulant use intensity (672 observations for daily stimulant users; 887 observations for non-daily stimulant users; 673 observations for stimulant non-users). Each point (middle panel) represents the estimated avoided costs and the error bars represent the95% confidence interval for each point. Points where the confidence interval does not include $0 reflect statistically significant amounts equivalent to those associated with a p-value <0.05. Mutually exclusive health states are: (i) MMT with high effectiveness (current MMT receipt and no illicit opioid use in the last six months); (ii) MMT with low effectiveness (defined as current MMT receipt with illicit opioid use in the last six months); (iii) opioid abstinence (defined as no current MMT receipt and no illicit opioid use in the last six months); or (iv) relapse (defined as no current MMT receipt with illicit opioid use in the last six months).