The National Institutes of Health (NIH) has announced a funding opportunity titled "Mechanistic Studies to Investigate the Interrelationship Between Sleep and/or Circadian Rhythms and Substance Use Disorders (R01 Clinical Trials Not Allowed)." This initiative aims to support basic science experimental studies that enhance understanding of the biological mechanisms linking sleep and circadian rhythms with substance use disorders (SUDs), focusing on how these factors influence substance use, dependence, withdrawal, and recovery. The NIH plans to allocate approximately $2 million for three to five projects, with each project eligible for a maximum direct cost of $300,000 per year for up to five years. Interested applicants must submit their proposals by October 30, 2024, and are required to include a Plan for Enhancing Diverse Perspectives (PEDP) and a Data Management and Sharing Plan. For further inquiries, applicants can contact NIH Grants Information at grantsinfo@nih.gov.