This K23 award will solidify the applicant’s capacity to conduct independent patient-focused, complementary and integrative health (CIH) research for mental health conditions, initially using a dietary supplement, with a unifying focus on emotional dysregulation, which cuts across mental health diagnoses and is a major source of clinical and functional impairment throughout the lifespan. Previous research of a multinutrient intervention by the applicant has demonstrated benefit for emotional dysregulation in pediatric ADHD populations. Because children with impairing emotional dysregulation have poor life outcomes despite existing treatments, demand for CIH interventions is high, yet most have little evidence of efficacy or safety, and their mechanisms of action are unknown. Further, current multinutrient research has not reflected the demographics of local populations and lacks clear understanding of biomarkers that can guide personalized care. The applicant proposes move the field forward on these related fronts. To inform a feasibility study the applicant will first run focus groups to understand the needs and priorities of local communities by discussing the child’s mental health needs and barriers to study participation. The qualitative results will guide study protocol and recruitment to test the feasibility and acceptability of a promising multinutrient intervention while testing refined data and biospecimen collection in local populations. The proposal goals are to enroll and retain participants that reflect the community’s demographics, while optimizing behavioral data and biospecimen collection procedures to reduce participant burden and facilitate participation. To achieve the goals, study will use real-time parent reports on their child’s behavior, recorded at home; a needle-free suction device for capillary blood, and filter cards for urine, participants will collect their specimens at home. Career development areas include appropriate engagement methods for a range of communities, integrating qualitative and quantitative data to identify community-generated priorities, knowledge in physiological systems (e.g. neuroimmune) to inform future biomarker investigation for personalized treatment approaches, and grant writing skills. In addition to testing the feasibility of a multinutrient for impairing emotional dysregulation, the study will lay the groundwork to examine possible biomarkers related to inflammation and neurotransmission, two hypothesized mechanisms of action. Career development will occur at an academic medical center under an interdisciplinary mentorship team of intellectually and diverse individuals. While this proposal focuses on ADHD and emotional dysregulation in children, the applicant’s training and results will be applicable to CIH research broadly, as the NCCIH prioritizes broad research representation and examining biomarkers for mechanistic signals. This K23 will provide the applicant with the training and preli...