Investigating psilocybin's effects on brain function in adults with and without autism

Modulation of Serotonin Pathways Using Psilocybin in Adults With and Without Autism Spectrum Disorder (ASD)

Not applicable Interventional King's College London · NCT05651126

This study is testing how a substance called psilocybin affects brain function in adults with and without autism to see if it changes how their brains respond to serotonin.

Quick facts

PhaseNot applicable
Study typeInterventional
Enrollment70 (estimated)
Ages18 Years to 60 Years
SexAll
SponsorKing's College London Academic / other
Locations1 site (London)
Trial IDNCT05651126 on ClinicalTrials.gov

What this trial studies

This study aims to explore how serotonin regulates brain systems differently in individuals with and without Autism Spectrum Disorder (ASD) by administering two doses of psilocybin and comparing the results to a placebo. Participants will undergo various brain assessments using MRI, EEG, and sensory tasks to evaluate their brain responses. The study will include adults over 18 years old who are in good physical health and can provide informed consent. The research is designed to enhance understanding of serotonin's role in ASD and its potential implications for treatment.

Who should consider this trial

Good fit: Ideal candidates for this study are adults aged 18 and older, both with and without a diagnosis of Autism Spectrum Disorder.

Not a fit: Patients who are pregnant, breastfeeding, or have a history of certain medical conditions may not benefit from this study.

Why it matters

Potential benefit: If successful, this study could provide insights into the neurobiological differences in serotonin regulation in individuals with ASD, potentially leading to new therapeutic approaches.

How similar studies have performed: While the use of psilocybin in clinical settings is gaining interest, this specific approach of comparing brain responses in autistic and non-autistic individuals is relatively novel.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

For all participants:

* Calendar age above 18 years
* Working knowledge of English
* Able to give informed consent
* Not pregnant or breastfeeding
* Individuals should be in good physical health, prescription medication free during the 2-week period preceding a study visit. However, occasional use of over-the-counter medication (e.g. painkillers) on an as needed basis (and not on the day of study visit) may be permitted. In addition, regular prescription medication (use of a stable dose over the two months preceding participation) with a drug that does not affect 5HT directly may be permitted. Also permitted is topical medication without systemic exposure

For individuals with ASD:

* Diagnosis of ASD by recognised clinical service supported by the Autism Diagnostic Interview-Revised (ADI-R) if a relative is available. Current symptom level assessed using the Autism Diagnostic Observation Schedule (ADOS-2)

Exclusion Criteria:

For all participants:

* History of allergy/idiosyncrasy to psilocybin or chemically related compounds or excipients which may be employed in the study or to any other drug used in the past
* Clinically relevant history or presence of any medical disorder, potentially interfering with this study
* Clinically relevant abnormality at screening as judged by the investigator
* History of or current abuse of drugs (including prescription medication) or alcohol or solvents
* Participation in a research study involving a pharmacological probe or drug trial within last month
* Subjects with current epilepsy, seizures or episodes of unexplained and unprovoked loss of consciousness
* Anyone with a history or examination which indicates laboratory testing is needed will be excluded from the study
* Intelligence Quotient below 70
* Currently taking prescription medications of propranolol or pindolol
* Individuals with major mental illness
* Individuals who have a current or past history of meeting diagnostic criteria for schizophrenia or other psychotic disorders or bipolar I or II disorder

Reproductive safety:

* Pregnancy or breastfeeding (is a routine exclusion for research MRI scanning)
* Female study participants must be willing to use one form of highly effective non-hormonal contraception for one week after study drug administration. This would include a vasectomised partner (sole partner), tubal occlusion, intrauterine system \[IUS\]/hormonal coil or copper containing intrauterine device or copper containing IUD, or true abstinence (when this is in line with the preferred and usual lifestyle of the subject). Women should have been stable on their chosen method of birth control for a minimum of 2 months before entering the study. Participants must agree to undergo a pregnancy test prior to each administration of study drug

For individuals with ASD:

ASD caused by a known genetic syndrome, e.g. Fragile X, 22q11 deletion syndrome.

Currently treated for epilepsy

Where this trial is running

London

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Autism Spectrum DisorderPsilocybinSerotoninPharmacological ImagingMRIEEGPsychedelics
Last reviewed 2026-06-09 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.