Do naloxone access laws affect perceived risk of heroin use? Evidence from national US data.

Background and aims: Whether expanded access to naloxone reduces perceptions of risk about opioid use has been subject to debate. Our aim was to assess how implementation of naloxone access laws shapes perceived risk of heroin use. Design: Using data from the restricted-access National Survey on Drug Use and Health, Prescription Drug Abuse Policy System and the US Census, we applied two-way fixed-effects models to determine whether naloxone access laws decreased perceived risk of any heroin use or regular heroin use. We used Bayes factors (BFs) to confirm evidence for null findings. Setting: United States. Participants: A total of 884 800 respondents aged 12 and older from 2004 to 2016. Measurements: A binary indicator of whether a state implemented naloxone access laws was regressed on respondent-perceived risk of (1) any heroin use and (2) regular heroin use. Ratings of perceived risk were assessed on a scale of 1 (none) to 4 (great risk). Findings: In all instances, the BFs support evidence for the null hypothesis. Across models with three distinct specifications of naloxone access laws, we found no evidence of decreased risk perceptions, as confirmed by BFs ranging from 0.009 to 0.057. Across models of specific vulnerable subgroups, such as people who use opioids (BFs = 0.039-0.225) or young people (BFs = 0.009-0.158), we found no evidence of decreased risk perceptions. Across diverse subpopulations by gender (BFs = 0.011-0.083), socio-economic status (BFs = 0.015-0.168) or race/ethnicity (BFs = 0.016-0.094), we found no evidence of decreased risk perceptions. Conclusions: There appears to be no empirical evidence that implementation of naloxone access laws has adversely affected perceptions of risk of heroin in the broader US population or within vulnerable subgroups or diverse subpopulations. [ABSTRACT FROM AUTHOR]