Leah K. Hamilton, PhD


“My work seeks to increase patients’ access to appropriate care for unhealthy alcohol and drug use. I am particularly interested in increasing access to substance use treatment and services for people with criminal justice system experiences.”

Leah K. Hamilton, PhD

Senior Collaborative Scientist, Kaiser Permanente Washington Health Research Institute


Leah Hamilton, PhD, MPhil, is an addiction health researcher focused on improving screening, assessment, and linkage to appropriate treatment and harm-reduction services for substance use disorders and associated behavioral health issues. She is particularly interested in improving access to these services among people involved in the criminal justice system through interventions rooted in implementation science.  

At KPWHRI, Dr. Hamilton is a collaborative researcher on 2 large pragmatic trials: the Primary Care Opioid Use Disorder Treatment (PROUD) trial and the Michigan Sustained Patient-centered Alcohol-Related Care (MI-SPARC) trial. The PROUD trial is a pragmatic implementation trial of nurse care management for treatment of opioid use disorders in primary care. Dr. Hamilton’s involvement includes analysis of quantitative outcome data including implementation and survey data. MI-SPARC is a multi-site implementation trial that seeks to improve alcohol screening within small primary care clinics in Michigan. Dr. Hamilton’s involvement in MI-SPARC includes the design, oversight, and analysis of study data.

Prior to joining KPWHRI, Dr. Hamilton completed her postdoctoral fellowship in the Department of Population Health at New York University Grossman School of Medicine, where she contributed to a Clinical Trial Network study of screening and assessment for substance use in primary care settings (CTN-0062Ot), and a National Institutes on Drug Abuse-funded R01 study (R01DA045872) examining the impact on overdose mortality of public health policies that aim either to restrict the supply of opioids or to reduce opioid-related harms. She completed her PhD in Criminal Justice at Temple University in Philadelphia in 2019, and MPhil at Cambridge University, Institute of Criminology, in the UK in 2010, during which she worked on multiple studies of substance use and behavioral health among justice-involved populations.

Areas of research focus

  • Addictions

    Screening, assessment, and linkage to care; addiction within justice-involved populations; harm reduction; policy impacts on overdose mortality

  • Behavior change

    Unhealthy alcohol and drug use, health-related quality of life (HRQoL)

  • Social determinants of health

    Justice involvement in addiction, and other aspects of behavioral and physical health

  • Health services & economics

    Implementation science; electronic health record (EHR)-integrated screening, assessment, and brief intervention/referral to care

  • Mental health

    Co-occurring substance-use and mental health disorders

Recent Publications

McNeely J, McLeman B, Gardner T, Nesin N, Amarendran V, Farkas S, Wahle A, Pitts S, Kline M, King J, Rosa C, Marsch L, Rotrosen J, Hamilton L. Implementation of substance use screening in rural federally-qualified health center clinics identified high rates of unhealthy alcohol and cannabis use among adult primary care patients. Addict Sci Clin Pract.. 2023 Sep 20;18(1):56. doi: 10.1186/s13722-023-00404-y. PubMed

Lapham GT, Matson TE, Bobb JF, Luce C, Oliver MM, Hamilton LK, Bradley KA. Prevalence of cannabis use disorder and reasons for use among adults in a US state where recreational cannabis use is legal. JAMA Netw Open. 2023 Aug 1;6(8):e2328934. doi: 10.1001/jamanetworkopen.2023.28934. PubMed

McClure EA, Hamilton L, Schauer GL, Matson TE, Lapham GT. Cannabis and nicotine co-use among primary care patients in a state with legal cannabis access.  Addict Behav. 2023;140:107621. doi: 10.1016/j.addbeh.2023.107621. Epub 2023 Jan 20. PubMed

Townsend TN, Hamilton LK, Rivera-Aguirre A, Davis CS, Pamplin JR, Kline D, Rudolph KE, Cerdá M. Use of an inverted synthetic control method to estimate effects of recent drug overdose good samaritan laws, overall and by Black/White race/ethnicity. Am J Epidemiol. 2022 Sep 28;191(10):1783-1791. doi: 10.1093/aje/kwac122. PubMed

Hamilton LK, Wheeler-Martin K, Davis CS, Martins SS, Samples H, Cerdá M. A modified Delphi process to identify experts' perceptions of the most beneficial and harmful laws to reduce opioid-related harm. Int J Drug Policy. 2022 Oct;108:103809. doi: 10.1016/j.drugpo.2022.103809. Epub 2022 Jul 28. PubMed




Increasing opioid use disorder treatment in primary care

A trial led by KPWHRI researchers found that adding nurse care managers helped more people get needed treatment.

Healthy Findings Blog


Talking to an addictions researcher

KPWHRI Collaborative Scientist Leah Hamilton, PhD, MPhil, answers questions about her recent and upcoming projects.

Mental Health


What’s the cost of mental health integration?

Kaiser Permanente Washington shows price may not be a barrier to primary care implementation, Dr. Kai Yeung reports.