Development and Validation of a Measure of Substance-Related Consequences: A Novel Clinical Outcome Assessment for Substance Use Disorder Trials - Although effective treatments have been developed for substance use disorders (SUDs), many people who receive treatment relapse or dropout of treatment prematurely. For many SUDs, treatment options are limited, particularly those for which there are currently no FDA-approved medications. Accordingly, there is an urgent need for new treatments for SUDs. New treatment development for SUDs has been hampered by the reliance on sustained abstinence as the sole acceptable outcome for FDA approval as well as the absence of well- validated outcome measures that assess symptoms beyond substance use alone. Critically, SUDs are not defined solely by substance use, but also by the negative consequences associated with substance use. These consequences are among the most important outcomes to patients and their families, and often motivate the decision to seek treatment. A measure of consequences would serve as a valuable endpoint for SUD trials and could represent a common metric for trials of different SUDs (e.g., opioid, stimulant) and for trials of treatment for polysubstance use. Furthermore, attempts to determine the impact of non-abstinent reductions in use (e.g., the benefits of reduction in days or quantity of use) require valid measures of functioning that are sensitive to change; a measure of consequences could fill this gap. The objective of RFA- DA-25-028 is to “support the development of Clinical Outcome Assessments for substance use disorders.” Consistent with this objective, our overarching aim is to develop and validate a novel clinical outcome assessment of substance-related consequences for use in SUD treatment trials. Study aims include to: identify item domains and refine a conceptual model of substance use consequences; develop a novel patient-reported outcome measure of substance use consequences; quantify the psychometric properties of the scale; and, determine the measure’s sensitivity to change during SUD treatment and its concordance with changes in substance use. To achieve our study aims, we will follow gold standard procedures for measure development and validation. The specific aims are aligned with benchmarks needed to ultimately seek approval from the FDA as a clinical outcome assessment that can be used to evaluate treatment efficacy. Our investigator team brings together experts in SUD treatment, clinical trials, and psychometrics to engage in a robust and rigorous scale development and validation process. Successful completion of these aims will contribute to our goal to establish a new clinical endpoint for SUD trials, with the goal of broadening the pipeline for promising new treatments to reduce the public health burden of SUDs.