The purpose of this funding opportunity is to support a multi-center consortium that will function as a clinical trials network to collect safety and early efficacy data in defined groups of older adults with specific chronic pain conditions. This funding opportunity will use a UG3/UH3 phased innovation mechanism, and responsive applications must include a research plan describing both UG3 and UH3 phases. UG3 (1st phase) studies, lasting up to 2 years, should involve preliminary studies in healthy older adults across a broad age range to evaluate safety, pharmacokinetic, and pharmacodynamic properties of psychedelic agents and preliminary testing of study elements that will inform further development and testing in the UH3 (2nd) phase. UH3 studies, lasting up to 3 years, should include expanded safety and preliminary efficacy studies in older adults with chronic pain conditions and include participants with non-contraindicated co-occurring conditions representative of real-world older adults. In both phases of the award, participants across a broad range of ages should be included, with particular attention to strata at the upper age range (i.e., 75-80 years, and 80+ years old). For the purposes of this RFA, the term psychedelic includes classic psychedelics, typically understood to be 5-HT2 agonists such as psilocybin,N,N-Dimethyltryptamine(DMT), lysergic acid diethylamide (LSD), and mescaline, as well as entactogens or empathogens such as methylenedioxymethamphetamine (MDMA). Synthetic analogs of these agents are also included. Cannabis, ketamine, and their related products are not considered psychedelic agents in this RFA.