Imperfect Substitutes: Examining whether and to what extent offering Opioid Subsitution Therapy (OST) may be increasing regional polydrug use

Abstract

Opioid Substitution Therapy (OST) attempts to curb opioid addiction by substituting a treatment opioid (i.e. methadone, buprenorphine, naltrexone, etc.) for an addict’s primary drug of abuse (i.e. heroin, oxycodone, etc.). However, insofar as patients continue abusing their preferred drug during treatment, OST programs may be increasing the absolute number of drugs patients are abusing. To the extent that some OST patients “divert” their treatment drugs into illicit markets, OST programs may also be increasing the absolute number of opioids abused by the surrounding population, as well. If corroborated, these trends would indicate a connection between OST treatments and the phenomenon most correlated with drug overdoses— “polydrug use,” or the concurrent use multiple drugs by one person.

To ascertain whether and to what extent OST treatment provisioning may be affecting regional polydrug use, this study models the annual number polydrug treatment episodes reported in a state as a function of that state’s OST patient population. The study relies primarily on two administrative datasets—the National Survey of Substance Abuse Treatment Services (N-SSATS) and the Treatment Episode Data Set-Admissions (TEDS-A)—collected between 2002 and 2006.

Using a two-way fixed-effects model that controlled for both state and annual fixed-effects, as well as for state populations and population densities, this study discovered a statistically significant positive correlation (p