An estimate of the number of people with clinical depression eligible for psilocybin-assisted therapy in the United States

This study aims to estimate the lower, middle, and upper bounds of potential demand for psilocybin-assisted therapy (PSIL-AT) for major depressive disorder (MDD) and treatment-resistant depression (TRD) in the United States. We calculated potential PSIL-AT demand for MDD and TRD by estimating the number of U.S. patients with MDD, identifying those in treatment, and determining who qualifies as having TRD. We established a range of estimates using the exclusion criteria from the largest trials to date on PSIL-AT for MDD or TRD. Estimates ranged from lower-bound through stringent criteria, mid-range by focusing on likely real-world scenarios, to upper-bound by accounting for double counting for patients with multiple comorbidities. A significant portion of patients with MDD and TRD is ineligible for PSIL-AT due to disqualifying conditions. Percentage of patients who are eligible are 24% (lower-bound), 56% (mid-range), and 62% (upper-bound). Variance was largely influenced by the removal of alcohol and substance use disorders as exclusion criteria, as well as removing the double counting from comorbid psychiatric and cardiovascular conditions. The analysis outlines the public health implications of providing PSIL-AT for MDD and TRD, emphasizing that the effective demand will be shaped by insurance coverage, state-level regulations, and the availability of trained providers. These findings suggest the need for careful policy planning and resource allocation to ensure equitable access and effective implementation of PSIL-AT across diverse populations and regions.