PSIL201 Long-term Follow-up Study: Psilocybin or Niacin / Major Depressive Disorder

A One-Year Observational Follow-up Study of Participants With Major Depressive Disorder Following a Randomized, Double-Blind Single-Dose of Psilocybin or Niacin-Control

This is a Phase 2 double-blind, long-term observational follow-up study of participants from Study PSIL201. Participants providing informed consent were enrolled into this study and completed web surveys and telephone interviews conducted by one central site at the following time intervals: months 3 and 6 (± 7 days for each assessment) and months 10 and 12 (± 14 days for each assessment).

Study Overview

• Status: Terminated
• Conditions: Major Depressive Disorder
• Intervention / Treatment: Other: No intervention will be administered as part of this study.

• Study Type: Observational
• Enrollment (Actual): 26

Contacts and Locations

Study Locations

• United States
  • Florida
    • Lauderhill, Florida, United States, 33319
      • Innovative Clinical Research, Inc. (formerly Segal Trials)

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 21 years to 65 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

Enrollment is constrained to those participants dosed with investigational drug (psilocybin or niacin) in Study PSIL201.

Description

Inclusion Criteria:

• Enrollment and randomization in Study PSIL201
• Ability and willingness to provide informed consent prior to initiation of any study-related procedures

Exclusion Criteria:

• Inability or unwillingness to complete study procedures, including regular completion of web surveys and telephone interviews with study personnel

Study Plan

How is the study designed?

Design Details

• Observational Models: Cohort
• Time Perspectives: Other

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Single-Dose of Psilocybin; Participants randomized to a single oral dose of psilocybin 25 mg in Study PSIL201.	Other: No intervention will be administered as part of this study.; No intervention will be administered as part of this study.
Niacin-Control; Participants randomized to a single oral dose of niacin 100 mg (active comparator) in Study PSIL201.	Other: No intervention will be administered as part of this study.; No intervention will be administered as part of this study.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Montgomery-Asberg Depression Rating Scale	Between-group difference in mean change from baseline (prior to dosing in PSIL201) in Montgomery-Asberg Depression Rating Scale (MADRS) to 6 months post-dosing in Study PSIL201	6 Months post-dosing in PSIL201

Collaborators and Investigators

• Sponsor: Usona Institute
• Investigators: Study Director: Charles Raison, MD, Usona Institute

Study record dates

Study Major Dates

• Study Start (Actual): June 30, 2020
• Primary Completion (Actual): October 18, 2022
• Study Completion (Actual): October 18, 2022

Study Registration Dates

• First Submitted: April 16, 2020
• First Submitted That Met QC Criteria: April 16, 2020
• First Posted (Actual): April 21, 2020

Study Record Updates

• Last Update Posted (Actual): May 4, 2026
• Last Update Submitted That Met QC Criteria: April 27, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Mental Disorders; Mood Disorders; Depressive Disorder; Depressive Disorder, Major
• Other Study ID Numbers: PSIL201-LTFU

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No