PROJECT SUMMARY The overarching goal of the proposed research is to evaluate the effectiveness of a systems-level secondary prevention strategy to prevent stimulant related overdoses. In 2020, 42% of overdose deaths in Denver involved methamphetamine. To date, a public health systems approach to enhance linkage and engagement in care for stimulant use disorder is lacking. Unlike opioid use disorder, for which medications relieve symptoms of acute withdrawal and prevent relapse, patients with stimulant use disorder present with methamphetamine- induced psychosis and are often combative, agitated, and difficult to treat. In response to community demands, our team at Denver Health recently established a pilot program, Beginning Early and Assertive Treatment for Methamphetamine Use Disorder (BEAT Meth), to protocolize the assessment and treatment of patients with methamphetamine use disorder. While the program has shown preliminary success in reducing hospital length of stay, readmissions, and improving follow-up to outpatient addiction treatment, it has not been rigorously evaluated and many patients are not retained in care after discharge. The proposed research will build upon BETH Meth's initial success by developing, implementing, and evaluating an intervention to better engage patients into ongoing care after discharge. The current application is in direct response to Objective 1 in the Centers for Disease Control and Prevention's notice of funding opportunity for ?Research Grants to Develop or Identify Effective Strategies to Prevent Overdose Involving Illicit Stimulants and Polysubstance Use Involving Stimulants.? Our multidisciplinary team brings together years of experience in substance use research, process and outcome evaluation, behavioral intervention development, addiction medicine, emergency medicine, psychiatry, and clinical care to address the following specific aims: 1) conduct a rigorous process evaluation of a newly developed protocol to identify and treat patients for stimulant use disorder in emergency settings, 2) develop and conduct process and outcomes evaluations of a linkage intervention aimed at increasing continuation and engagement in treatment, and 3) develop a systems-level stimulant continuum of care model to measure the progression of patients with stimulant-related problems and the effectiveness of health system protocols and interventions on patients along that continuum. Our novel public health systems approach leverages partnerships among public health, public safety, and health systems to provide accessible, scalable, and effective treatments for stimulant use disorder. Our findings will provide empirical evidence for a replicable systems-level intervention to increase initiation, guide treatment provision, and reduce morbidity and mortality associated with the overdose crisis.