Predictors of US states’ adoption of naloxone access laws, 2001–2017

Background: The opioid crisis has put an increasing strain on US states over the last two decades. In response, all states have passed legislation to implement a portfolio of policies to address the crisis. Although effects of some of these policies have been studied, research into factors associated with state policy adoption decisions has largely been lacking. We address this gap by focusing on factors associated with adoption of naloxone access laws (NAL), which aim to increase the accessibility and availability of naloxone in the community as a harm reduction strategy to reduce opioid-related morbidity and mortality. Methods: We used event history analysis (EHA) to identify predictors of the diffusion of naloxone access laws (NAL) from 2001, when the first NAL was passed, to 2017, when all states had adopted NAL. A variety of state characteristics were included in the model as potential predictors of adoption. Results: We found that state adoption of NAL increased gradually, then more rapidly starting in 2013. Consistent with this S-shaped diffusion process, the strongest predictor of adoption was prior adoption by neighboring states. Having a more conservative political ideology and having a higher percentage of residents who identified as evangelical Protestants were associated with later adoption of NAL. Conclusion: States appear to be influenced by their neighbors in deciding whether and when to adopt NAL. Advocacy for harm reduction policies like NAL should take into account the political and religious culture of a state.