PROJECT SUMMARY This K23 award will solidify the applicant’s capacity to conduct independent patient-focused, multicomponent dietary supplement clinical trials for mental health conditions. This proposal focuses on attention-deficit/hyperactivity disorder (ADHD) in children. ADHD is a central element in an early causal pathway to future depression, anxiety disorders, substance misuse, job and relationship failures, chronic health problems, suicide, and premature death. It is, therefore, a major public health priority. Perhaps the most impairing single feature of ADHD, which cuts across disorders and remains difficult to treat, is extreme emotional dysregulation (anger, moodiness, and irritability). The candidate has conducted clinical trials in children and adults with ADHD and emotional dysregulation that have shown benefit for a multinutrient dietary supplement containing all known vitamins and essential minerals. Limiting the reach and generalizability of this promising intervention, previous studies have included a majority of white, non-Hispanic participants; imprecise behavior change data; and limited examination of the multinutrients’ mechanisms of action. This proposal addresses these key issues. Aim 1 proposes a community-based, qualitative study using focus groups with Black and Hispanic parents to elicit their priorities concerning their child’s mental health and barriers to participation in research. Aims 2 and 3 propose a feasibility and acceptability study (pilot clinical trial) of the intervention in Black and Hispanic children. The study design will be informed by focus group feedback. Aim 2 tests real-time parent-reported behavior change in their child based on a targeted problem identified by the parent. Aim 3 tests the at-home biospecimen collection of blood and urine to initiate an examination of immune and neurotransmitter biomarker signals. Career development areas align closely with the research aims, and include training in community engagement and mixed methods to identify mental health priorities of diverse communities; mediator/moderator models and neuroimmune factors that affect mental health in order to initiate biomarker investigation; and professional development including leadership and grant writing skills. Career development will occur at a resource-rich academic medical center. The application is bolstered by an interdisciplinary mentor team of intellectually, racially, and ethnically diverse individuals. While this proposal focuses on ADHD and emotional dysregulation in children, the applicant’s training and proposal results are expected to generalize to CIH research broadly, as the NCCIH prioritizes increasing research participant diversity and examining biomarkers for mechanistic signals. This K23 will provide the applicant with the training and preliminary data to be competitive for an R01 study of the promising multinutrient intervention using refined data and biospecimen collection methods in a larger, di...