New Report Estimates Potential Demand of Psilocybin-Assisted Therapy for MDD

Syed Fayzan Rab, MD candidate

Credit: Emory University, Center for Psychedelics and Spirtuality

A new report estimates the potential demand for psilocybin-assisted therapy (PSIL-AT) for major depressive disorder (MDD) and treatment-resistant depression (TRD) in the United States.¹

“Our findings suggest that if the FDA gives the green light, psilocybin-assisted therapy has the potential to help millions of Americans who suffer from depression,” said lead author Syed Fayzan Rab, an Emory University MD candidate. ² “This underscores the importance of understanding the practical realities of rolling out this novel treatment on a large scale.”

The US Food and Drug Administration (FDA) designated PSIL-AT as a breakthrough therapy for patients with either MDD or TRD.¹ The FDA has previously voiced concerns about psychedelic-assisted therapy at the advisory committee meeting and later issued a complete response letter (CRL) for MDMA-assisted therapy new drug application to treat PTSD.³

However, the FDA is now considering the approval of psilocybin-assisted therapy.¹ Clinical trials have already defined inclusion and exclusion criteria for MDD and TRD. Examples of disqualifying comorbidities include psychotic or mania disorder, suicide attempt in the past year, uncontrolled diabetes, stroke, heart attack in last year, BP140+/90+, epilepsy, personality disorder, hepatic impairment, alcohol dependence, drug dependence, other cardiac conditions, and received ECT or TMS in the past 90 days.

In this study, investigators sought to estimate the lower, middle, and upper bounds of potential demand for PSIL-AT for MDD and TRD in the US. The team calculated the potential demand by estimating the number of US patients with MDD, identifying those in treatment, and determining who qualifies as having TRD.

Using exclusion criteria from the current largest trials on PSIL-AT for MDD or TRD, the team established a range of estimates. Investigators wanted to determine the number of individuals who may qualify for this innovative treatment approach when considering potential disqualification conditions.

“Our estimates of demand are subject to contingencies pending FDA decision around PSILAT,” investigators explained.

The team created estimates based on stringent criteria (lower-bound), focusing on likely real-world scenarios (mid-range), and accounting for double counting for patients with multiple comorbidities (upper-bound). Before creating estimates, investigators discovered that, among the 14.8 million people in the US with MDD, 9 million receive symptom relief with treatments and 2.7 million meet the criteria for TRD.

The report showed a significant portion of patients with MDD and TRD are ineligible for PSIL-AT due to disqualification. The lower-bound estimate suggests only 24% of patients with depression would meet strict clinical trial exclusion criteria for PSIL-AT, amounting to 2.2 million patients currently undergoing treatment for MDD or 0.6 million patients with TRD.

Furthermore, when considering exclusion criteria likely to operate in real-world clinical settings (the mid-range estimate), 56% of participants with MDD were eligible. This equates to 5.1 million patients with MDD and 1.5 million with TRD who would be eligible for PSIL-AT—excluding participants with alcohol and substance use disorder accounting for 32% of the difference.

The upper-bound estimate, adjusting for double counting between different medical conditions, showed 62% of patients with depression are eligible for PSIL-AT. This accounts for 5.6 million individuals with MDD and 1.7 million individuals with TD who are eligible for PSIL-AT. Accounting for the co-occurrence of cardiovascular and psychiatric comorbidities contributed to a 3% - 4% increase in eligibility.

The sensitivity analysis showed a potential variability in their estimates based on changes in the assumptions underlying comorbidity prevalence for eligible patients with MDD (95% confidence interval [CI], 4.7 million to 6.6 million eligible individuals) and TRD (95% CI, 1.4 million to 1.9 million).

“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,” investigators wrote.

References

1. ^{Rab, S, Raison, C, Marseille, E, et al. Annestimate of the number of people with clinical depression eligible for psilocybin-assisted therapy in the United States. Psychedelics; https://doi.org/10.61373/pp024r.0025}
2. ^{Millions of depressed Americans could benefit from psychedelic therapy, study finds. EurekAlert! September 13, 2024. https://www.eurekalert.org/news-releases/1057531. Accessed September 17, 2024.}
3. ^{Deman, C. FDA Rejects Application for MDMA-Assisted Therapy in PTSD, Calls for Additional Trial. HCPLive. August 9, 2024. https://www.hcplive.com/view/fda-rejects-application-for-mdma-assisted-therapy-in-ptsd-calls-for-additional-trial. Accessed September 17, 2024.}