Polysubstance Use: A Broader Understanding of Substance Use During the Opioid Crisis

<i>Objectives.</i> To understand important changes in co-occurring opioid and nonopioid drug use (i.e., polysubstance use) within the opioid epidemic in the United States.<i>Methods.</i> We analyzed survey data on the past month co-use of prescription and illicit opioids and 12 nonopioid psychoactive drug classes from a national sample of 15 741 persons entering treatment of opioid use disorder.<i>Results.</i> Past-month illicit opioid use increased from 44.8% in 2011 to 70.1% in 2018, while the use of prescription opioids alone dropped from 55.2% to 29.9%, yet overall remained high (94.5% to 85.2%). Past-month use of at least 1 nonopioid drug occurred in nearly all participants (> 90%), with significant increases in methamphetamine (+85%) and decreases across nonopioid prescription drug classes (range: -40% to -68%).<i>Conclusions.</i> Viewing opioid trends in a "silo" ignores the fact not only that polysubstance use is ubiquitous among those with opioid use disorder but also that significant changes in polysubstance use should be monitored alongside opioid trends.<i>Public Health Implications.</i> Treatment, prevention, and policymaking must address not only the supply and demand of a singular drug class but also the global nature of substance use overall.