The National Institutes of Health (NIH) is inviting applications for the NIDA Program Project Grant (P01 Clinical Trial Optional), aimed at supporting collaborative, multidisciplinary research addressing critical issues related to substance use and its consequences. This funding opportunity requires applicants to propose a minimum of three interrelated research projects that demonstrate scientific merit and thematic cohesion, supported by an administrative core, to foster synergistic outcomes that enhance the overall program's impact. This initiative reflects NIH's commitment to advancing addiction research through collaboration across various fields, including neuroscience, genetics, and health services. Interested applicants, including higher education institutions and nonprofit organizations, must submit their proposals by January 7, 2026, and can find additional information and application guidelines at NIH Grants. For inquiries, contact NIH Grants Information at grantsinfo@nih.gov.