Using Multivariate Mixture Models to Study Polysubstance Use with Methamphetamine in Nationally Representative and Population Samples - PROJECT SUMMARY/ABSTRACT Methamphetamine (METH) past-year use prevalence has doubled since 2015 (from 0.51% to 1.11%), as have METH-involved deaths. METH use represents a significant threat to public health and a challenge to treatment efforts, as METH use is associated with substantial negative impacts on mental and physical health. There are currently no effective pharmacological treatments for METH use disorder (MUD), and cognitive and behavioral therapies remain difficult to access for people with MUD. Co-use of other substances (polysubstance use) and high likelihood of developing substance use disorders are central features of METH use that increase risk for poor treatment outcomes and contribute to METH’s disproportionate public health burden. Recent population- level data shows that 78.2% of MUD treatment cases involve other substance use disorders. To date, studies have focused on effects of METH use in combination with one or two other substances (e.g., opioids), but other substances are highly prevalent among METH users and complicate the understanding of METH’s influence on mental health, physical health and the course of METH treatment. This project aims to fill gaps in the current literature by identifying “types” of polysubstance use with METH in the US, which may better predict outcomes and inform the implementation and development of MUD interventions across treatment settings. This project will be supported by an interdisciplinary mentorship team with relevant and complimentary expertise and the rich substance use research and training environment at the University of California, San Diego (UCSD) HIV Neurobehavioral Research Program (HNRP). The proposed R36 will utilize multivariate mixture models, large computational structures, and two large, publicly available data sources: National Survey on Drug Use and Health (NSDUH, 2015-2022) and Treatment Episodes Data Sets (TEDS, 2018-2021), which are published and maintained by the Substance Abuse and Mental Health Services Administration. This proposal specifically aims to 1) provide an updated epidemiological understanding of polysubstance use with METH in the US, 2) identify clinically distinct subpopulations of people who use METH and examine how these differ in demography, medical and mental health, treatment history and access, and MUD treatment outcome, and 3) identify common histories of substance use initiation prior to METH and examine their relationship with demography, current medical and mental health, treatment history and access, and current MUD. These aims are consistent with the National Institute on Drug Abuse’s strategic plan to identify what substances are being used in combination, by whom, and how these combinations may influence differential outcomes. Completion of this R36 proposal will allow me to fulfill the doctoral dissertation requirements for a PhD in clinical psychology and expand my foundational research skills, which I aim to leverage in building my career as an independent investigator, focused on understanding “real world” substance use and its impact on mental and physical health.
