The ENHANCE Study: taVNS and Psilocybin (ENHANCE)

Activating Neuroplasticity to ENHANCE the Perception Box Expanding Effects of Psilocybin

This study will examine whether combining a single dose of psilocybin with non-invasive transcutaneous auricular vagus nerve stimulation (taVNS), a potential inducer of neuroplasticity and enhanced memory formation, will enhance the long-term beneficial behavioral effects of psilocybin when compared to sham taVNS or no VNS by allowing memory for insights gained during the psychedelic experience to remain vivid after they will have faded in subjects who receive psilocybin followed by sham taVNS or no VNS.

Study Overview

• Status: Recruiting
• Conditions: Healthy; Vagus Nerve Stimulation; Psychedelic Experiences
• Intervention / Treatment: Drug: Psilocybin; Device: Transcutaneous auricular Vagus Nerve Stimulation (taVNS); Other: Sham taVNS; Behavioral: Psychosocial Support Alone

Detailed Description

One hundred and eight medically healthy adult volunteers with a modest decrement in wellbeing will receive a single open-label 25 mg dose of psilocybin administered within a "set and setting" (SaS) framework of psychological support provided by trained facilitators, such as has been successfully employed in prior psychedelic studies at UW-Madison. The SaS protocol will include 2-4 hours of preparation, a 6- to 8-hour psilocybin dosing session and an hour-long integration session 1 day and 9 days post dosing. All subjects will receive various combinations of active taVNS or sham taVNS prior to, or following, psilocybin dosing.

Active and sham taVNS sessions will last 20 minutes and will occur twice daily (morning and afternoon/evening) for 7 consecutive days, using an "at home" protocol that has been used safely and effectively by study collaborators. taVNS is a non-invasive low-risk procedure.

Subjects will be randomized with equal allocation to one of four conditions: 1) seven days of sham taVNS prior to psilocybin dosing and 7 days of active taVNS post- psilocybin dosing (Group 1: n=27); 2) seven days of sham taVNS prior to psilocybin dosing and 7 days of sham taVNS post- psilocybin dosing (Group 2: n=27); 3) seven days of sham taVNS prior to psilocybin dosing and psilocybin with psychosocial support post-dosing (Group 3: n=27); and 4) seven days of active taVNS prior to psilocybin dosing and 7 days of sham taVNS post- psilocybin dosing (Group 4: n=27). Importantly, participants in all groups will receive psychosocial support in addition to their randomization status (i.e., taVNS or sham taVNS prior to, or following psilocybin, or psychosocial support alone), as the provision of psychosocial support is the current standard of care for the use of psychedelics in FDA-regulated clinical trials (FDA 2023). It is anticipated that a total sample of 108 subjects will be enrolled to provide 100 subjects who complete study activities/assessments sufficient to provide evaluable data for testing study primary and exploratory outcomes.

• Study Type: Interventional
• Enrollment (Estimated): 108
• Phase: Phase 1

Contacts and Locations

• Study Contact: Name: Program Manager; Phone Number: 608-265-4987; Email: enhance@psychiatry.wisc.edu

Study Locations

• United States
  • Wisconsin
    • Madison, Wisconsin, United States, 53715
      • Recruiting
      • University of Wisconsin - Madison
      • Sub-Investigator: Christopher Nicholas, PhD
      • Contact: Program Manager; Email: enhance@psychiatry.wisc.edu

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• English speaking
• Ability/willingness to complete all study activities
• Modest reduction in emotional well-being
• Medically healthy (does not meet criteria for an exclusionary medical condition)
• Blood pressure and heart rate within established ranges at screening
• Use of acceptable contraceptive methods (sexually active males and women of childbearing potential)

Exclusion Criteria:

• Clinically significant safety lab abnormalities (i.e., Complete Blood Count with Differential, Comprehensive Metabolic Panel, and urinalysis)
• Current or clinically significant psychiatric disorder that, in the investigator's judgment, would interfere with participation or increase risk
• Current use of drugs or medications, prescribed or otherwise, that may interact with psilocybin
• Use of investigational drugs, biologics, or devices within 30 days of enrollment
• Use of psychedelic or related agents within three months of Dosing Day
• Clinically significant electrocardiogram (ECG)
• Vitals outside acceptable range
• Pregnancy and currently breastfeeding
• Unwillingness to go without tobacco products for 12 hours or more
• Inability to undergo fMRI scanning
• Recent ear trauma, hearing loss (if clinically significant), or deafness
• Family history of a psychotic disorder in a first degree relative

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Factorial Assignment
• Masking: Triple

Number of Arms

4

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Group 1: Sham taVNS + Psilocybin + taVNS; Group 1 will receive twice daily sham taVNS for 7 days immediately prior to psilocybin dosing. Post-psilocybin dosing, they will receive twice-daily taVNS paired with psychedelic session contextual cues for 7 days.	Drug: Psilocybin; The psilocybin is produced under Good Manufacturing Practice and is in a capsule that contains 25 mg of botanically-derived psilocybin.; Other Names: PEX010; Psilocybine, Psilocibin; Filament Health Psilocybin; Device: Transcutaneous auricular Vagus Nerve Stimulation (taVNS); For both the active and sham taVNS procedure, participants will be provided with, and trained on, taVNS devices that apply gentle stimulation to the left ear via either electrodes or an earpiece that fits over the left ear.; Other: Sham taVNS; For both the active and sham taVNS procedure, participants will be provided with, and trained on, taVNS devices that apply gentle stimulation to the left ear via either electrodes or an earpiece that fits over the left ear.
Sham Comparator: Group 2: Sham taVNS + Psilocybin + Sham taVNS; Group 2 will receive twice daily sham taVNS for 7 days immediately prior to psilocybin dosing. Post-psilocybin dosing, they will receive twice-daily sham taVNS paired with psychedelic session contextual cues for 7 days.	Drug: Psilocybin; The psilocybin is produced under Good Manufacturing Practice and is in a capsule that contains 25 mg of botanically-derived psilocybin.; Other Names: PEX010; Psilocybine, Psilocibin; Filament Health Psilocybin; Other: Sham taVNS; For both the active and sham taVNS procedure, participants will be provided with, and trained on, taVNS devices that apply gentle stimulation to the left ear via either electrodes or an earpiece that fits over the left ear.
Active Comparator: Group 4: taVNS + Psilocybin + Sham taVNS; Group 4 will receive twice daily taVNS for 7 days immediately prior to psilocybin dosing. Post-psilocybin dosing, they will receive twice-daily sham taVNS paired with psychedelic session contextual cues for 7 days.	Drug: Psilocybin; The psilocybin is produced under Good Manufacturing Practice and is in a capsule that contains 25 mg of botanically-derived psilocybin.; Other Names: PEX010; Psilocybine, Psilocibin; Filament Health Psilocybin; Device: Transcutaneous auricular Vagus Nerve Stimulation (taVNS); For both the active and sham taVNS procedure, participants will be provided with, and trained on, taVNS devices that apply gentle stimulation to the left ear via either electrodes or an earpiece that fits over the left ear.; Other: Sham taVNS; For both the active and sham taVNS procedure, participants will be provided with, and trained on, taVNS devices that apply gentle stimulation to the left ear via either electrodes or an earpiece that fits over the left ear.
Active Comparator: Group 3: Sham taVNS + Psilocybin + Psychosocial Support Alone; Group 3 will receive twice daily sham taVNS for 7 days immediately prior to psilocybin dosing. Post-psilocybin dosing, they will receive psychosocial support alone, comprised of an integration session 1 day and 1-week post-psilocybin dosing. They will not receive active or sham taVNS post-psilocybin.	Drug: Psilocybin; The psilocybin is produced under Good Manufacturing Practice and is in a capsule that contains 25 mg of botanically-derived psilocybin.; Other Names: PEX010; Psilocybine, Psilocibin; Filament Health Psilocybin; Other: Sham taVNS; For both the active and sham taVNS procedure, participants will be provided with, and trained on, taVNS devices that apply gentle stimulation to the left ear via either electrodes or an earpiece that fits over the left ear.; Behavioral: Psychosocial Support Alone; Participants assigned to Psychosocial Support Alone will not receive taVNS following psilocybin dosing.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Functional Magnetic Resonance Imaging (fMRI): Comparison of taVNS Administration vs. Treatment as Usual	Activation in brain regions associated with cued autobiographical memory retrieval will be assessed with fMRI. Group comparisons will examine differences in whole brain blood oxygenated level dependent (BOLD) signal and connectivity based on previously established seed-based methods using a priori brain regions implicated in autobiographical memory retrieval corresponding dosing session stimuli. The study team will update with more specific information when the details are confirmed.	Day 1 and Day 56 Post- Psilocybin Dose
Warwick-Edinburgh Mental Wellbeing Scale (WEMWBS): Comparison of taVNS Administration vs. Treatment as Usual	The WEMWBS is a 14-item self-report scale that was designed to measure the psychological well-being of a population. The questions use a five-point Likert scale. The items are all worded positively and cover both feeling and functioning aspects of mental wellbeing. Items on the questionnaire are rated on a 5-point scale, where 1= "None of the time", 2= "rarely", 3= "some of the time", 4= "often", 5= "all the time". A total scale score is calculated by summing the 14 individual item scores. The total possible range of scores for the WEMWBS is 14-70 with higher scores indicating a greater well-being.	8 weeks
Summary of Adverse Events	Adverse events (AEs) categorized by CTCAE v5.0 criteria at all assessments (6 study visits).	up to 8 weeks
Memory Experiences Questionnaire (MEM-Q-PSIL): Comparison of taVNS Administration vs. Treatment as Usual	The MEM-Q is 31-item self-report scales designed to measure 10 phenomenological qualities of autobiographical memories: Vividness, Coherence, Accessibility, Time Perspective, Sensory Details, Visual Perspective, Emotional Intensity, Sharing, Distancing and Valence. Ratings are made on a 5-point Likert scale, ranging from 1 (strongly disagree) to 5 (strongly agree).	8 weeks

Collaborators and Investigators

• Sponsor: University of Wisconsin, Madison
• Collaborators: Tiny Blue Dot Foundation
• Investigators: Principal Investigator: Charles Raison, MD, University of Wisconsin, Madison

Publications and helpful links

Helpful Links

• Take the pre-screening survey

Study record dates

Study Major Dates

• Study Start (Actual): January 27, 2025
• Primary Completion (Estimated): November 1, 2027
• Study Completion (Estimated): January 1, 2028

Study Registration Dates

• First Submitted: May 10, 2023
• First Submitted That Met QC Criteria: May 10, 2023
• First Posted (Actual): May 19, 2023

Study Record Updates

• Last Update Posted (Actual): April 3, 2026
• Last Update Submitted That Met QC Criteria: March 31, 2026
• Last Verified: March 1, 2026

More Information

Terms related to this study

• Keywords: Healthy Volunteer; Vagus Nerve Stimulation; Psilocybin; Psychedelics
• Additional Relevant MeSH Terms: Heterocyclic Compounds; Heterocyclic Compounds, 2-Ring; Heterocyclic Compounds, Fused-Ring; Therapeutics; Alkaloids; Indoles; Health Services; Health Care Facilities Workforce and Services; Rehabilitation; Indole Alkaloids; Indolizidines; Indolizines; Tryptamines; Psilocybin; Psychiatric Rehabilitation
• Other Study ID Numbers: 2024-0463; A538900 (Other Identifier: UW Madison); Protocol Version 12/30/25 (Other Identifier: UW Madison)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: De-identified data including, but not limited to, demographics, questionnaires, adverse events, and fMRI data may be made available to qualified researchers upon request.
• IPD Sharing Time Frame: Following publication of primary study findings.

IPD Sharing Access Criteria

All de-identified data will be made available to qualified researchers in a way that protects subject confidentiality and adheres to HIPAA policies. Both internal and external requests for data will be handled by the Principal Investigator (PI) to ensure equitable access, fairness, and safeguards. After reviewing a short proposal prepared by an external investigator, the PI will approve requests with appropriate experimental design, scientific merit, and Institutional Review Board (IRB) approval and recommend revisions for proposals requiring further justification or modifications. Informed consent documents will provide sufficient detail about the intent to archive, share, and re-analyze data.

MRI data will also be shared upon request using the same data sharing process described above. To facilitate interpretation of the data, imaging parameters, gender, age, and racial information will be shared and associated with the dataset.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No