Autism Spectrum DisorderPSILAUTNCT05651126
Psilocybin in Adults With and Without Autism Spectrum Disorder
A study testing Psilocybin 5 mg and Psilocybin 2 mg in people with Autism Spectrum Disorder, run by King's College London at 1 site in United Kingdom.
Trial summary
This study will test the hypothesis that brain systems are differentially regulated by serotonin in individuals with and without Autism Spectrum Disorder. Read more about this study
- Who is it for?
- Ages 18 to 60 yearsHealthy volunteers can take part
- Conditions the study is for
- Autism Spectrum Disorder
- What is being tested?
- Psilocybin 5 mg and Psilocybin 2 mg
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 67 participants
- Where
- 1 siteUnited Kingdom
- Study dates
- 12 Dec 2022to 23 Aug 2024
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 60 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- 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)
Who cannot join
- 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
Show all 18Show fewer
- 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
Trial locations and contacts
1 site in 1 country.
About this study
Official title: Modulation of Serotonin Pathways Using Psilocybin in Adults With and Without Autism Spectrum Disorder (ASD)
This study will test the hypothesis that brain systems are differentially regulated by serotonin in individuals with and without Autism Spectrum Disorder.
Read the detailed description
To do this, the brain response to two single acute doses of partial serotonin (5HT)1A/2A receptor agonist psilocybin (COMP360) relative to a single dose of placebo (baseline serotonin activity) will be compared in healthy autistic and non-autistic adults.
Brain function will be assessed using a range of MRI (fMRI and MRS), EEG and sensory tasks. Unimodal and multimodal analyses will be conducted.
Please note that this study uses psilocybin as a probe of the serotonin system in a Case-Control science study and, following Scope protocol review, the U.K. MHRA confirmed that it is not a 'Clinical Trial of an Investigational Medicinal Product' (IMP) as defined by the EU Directive 2001/20/EC.
- Conditions
- Autism Spectrum Disorder
- Being tested
- Psilocybin 5 mg, Psilocybin 2 mg, Placebo
- Keywords
- Autism Spectrum Disorder, Psilocybin, Serotonin, Pharmacological Imaging, MRI, EEG, Psychedelics
- Medical subject headings
- Autism Spectrum Disorder
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Psilocybin 5 mgDrug
Also called COMP360
Partial Serotonin (5HT) 1A/2A Receptor Agonist Psilocybin
Psilocybin 2 mgDrug
Also called COMP360
Partial Serotonin (5HT) 1A/2A Receptor Agonist Psilocybin
PlaceboDrug
Inactive placebo
| Study group | Role | What they receive |
|---|---|---|
| Placebo, Psilocybin_2, Psilocybin_5 | Experimental | Dose order: Placebo, Psilocybin 2mg, Psilocybin 5mg Receives: Drug: Psilocybin 5 mg; Drug: Psilocybin 2 mg; Drug: Placebo |
| Psilocybin_2, Placebo, Psilocybin_5 | Experimental | Dose order: Psilocybin 2mg, Placebo, Psilocybin 5mg Receives: Drug: Psilocybin 5 mg; Drug: Psilocybin 2 mg; Drug: Placebo |
| Psilocybin_2, Psilocybin_5, Placebo | Experimental | Dose order: Psilocybin 2mg, Psilocybin 5mg, Placebo Receives: Drug: Psilocybin 5 mg; Drug: Psilocybin 2 mg; Drug: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Brain activation and connectivity response to serotonergic stimulation as assessed by functional magnetic resonance imaging.
Comparing whole brain blood-oxygen-level-dependent (BOLD) activation (institutional units) during the resting state in cases and controls when the serotonin system is activated by a single oral dose of psilocybin (COMP360) versus the placebo condition.
Measured: Data collected on up to 3 visit days per participant.
Brain electrophysiological activity task-free electroencephalography (EEG)
Case-control comparison of task-free EEG by time-frequency analysis during placebo and when serotonin system is activated with psilocybin.
Measured: Data collected on up to 3 visit days per participant.
Brain electrophysiological activity electroencephalography (EEG) during visual stimulation
Case-control comparison of EEG Evoked Potentials in response to visual stimulation during placebo and when serotonin system is activated with psilocybin.
Measured: Data collected on up to 3 visit days per participant.
Brain electrophysiological activity electroencephalography (EEG) during auditory stimulation
Case-control comparison of EEG Event Related Potentials in response to auditory tones during placebo and when serotonin system is activated with psilocybin.
Measured: Data collected on up to 3 visit days per participant.
Secondary outcomes (1)
Brain excitation and inhibition response to serotonergic stimulation as assessed by magnetic resonance spectroscopy.
Quantification and case-control comparison of brain metabolites relevant to regulation of excitation and inhibition (focus on Glx, GABA, GSH) using proton magnetic resonance spectroscopy when serotonin system is 'at rest' (placebo) and when activated by psilocybin.
Measured: Data collected on up to 3 visit days per participant.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted14 Dec 2022
- Study start12 Dec 2022
- Primary completion23 Aug 2024
- Study completion23 Aug 2024
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for Autism Spectrum DisorderStudies of the same condition, open and under way.
- More trials run by King's College LondonThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Model description
- Case-Control comparison using repeated-measures cross-over design. Each participant receives each one of the three pharmacological probes in separate visits (i.e., placebo, psilocybin low dose and psilocybin higher dose), with the order of administration being pseudorandomized (to prevent order effects).
- Masking
- Double blind
- Who is masked
- Participant, Investigator
- Enrolment
- 67 participants (actual)
Sponsor and investigators
- Lead sponsor
- King's College London
- Sponsor type
- University, hospital or other
- Collaborators
- University of Cambridge
- Responsible party
- Principal investigator, Dr Grainne McAlonan, King's College London
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05651126
- Sponsor's protocol ID
- IRAS: 292281; REC: 21/LO/0795
- Acronym
- PSILAUT
- Status last verified
- Mar 2024
- First submitted
- 11 Nov 2022
- Last updated
- 28 Jul 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Publications
Whelan TP, Daly E, Puts NA, Smith P, Allison C, Baron-Cohen S, Malievskaia E, Murphy DGM, McAlonan GM. The 'PSILAUT' protocol: an experimental medicine study of autistic differences in the function of brain serotonin targets of psilocybin. BMC Psychiatry. 2024 Apr 25;24(1):319. doi: 10.1186/s12888-024-05768-2.
PubMed 38658877
Study at a glance
From the registry record, last updated by the sponsor on 28 Jul 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Modulation of Serotonin Pathways Using Psilocybin in Adults With and Without Autism Spectrum Disorder (ASD)
- ClinicalTrials.gov ID
- NCT05651126
- Acronym / sponsor ID
- PSILAUT / IRAS: 292281; REC: 21/LO/0795
- Conditions
- Autism Spectrum Disorder
- Keywords
- Autism Spectrum Disorder, Psilocybin, Serotonin, Pharmacological Imaging, MRI, EEG, Psychedelics
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 67 participants (actual)
- Lead sponsor
- King's College LondonUniversity, hospital or other
- Collaborators
- University of Cambridge
- Study start
- 12 Dec 2022 (actual)
- Primary completion
- 23 Aug 2024 (actual)
- Study completion
- 23 Aug 2024 (actual)
- First posted
- 14 Dec 2022 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This study will test the hypothesis that brain systems are differentially regulated by serotonin in individuals with and without Autism Spectrum Disorder.
Detailed description
To do this, the brain response to two single acute doses of partial serotonin (5HT)1A/2A receptor agonist psilocybin (COMP360) relative to a single dose of placebo (baseline serotonin activity) will be compared in healthy autistic and non-autistic adults.
Brain function will be assessed using a range of MRI (fMRI and MRS), EEG and sensory tasks. Unimodal and multimodal analyses will be conducted.
Please note that this study uses psilocybin as a probe of the serotonin system in a Case-Control science study and, following Scope protocol review, the U.K. MHRA confirmed that it is not a 'Clinical Trial of an Investigational Medicinal Product' (IMP) as defined by the EU Directive 2001/20/EC.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Double blind (participant, investigator)
- Number of arms
- 3
- Model description
- Case-Control comparison using repeated-measures cross-over design. Each participant receives each one of the three pharmacological probes in separate visits (i.e., placebo, psilocybin low dose and psilocybin higher dose), with the order of administration being pseudorandomized (to prevent order effects).
| Arm | Type | Receives |
|---|---|---|
| Placebo, Psilocybin_2, Psilocybin_5 | Experimental | Drug: Psilocybin 5 mg, Drug: Psilocybin 2 mg, Drug: PlaceboDose order: Placebo, Psilocybin 2mg, Psilocybin 5mg |
| Psilocybin_2, Placebo, Psilocybin_5 | Experimental | Drug: Psilocybin 5 mg, Drug: Psilocybin 2 mg, Drug: PlaceboDose order: Psilocybin 2mg, Placebo, Psilocybin 5mg |
| Psilocybin_2, Psilocybin_5, Placebo | Experimental | Drug: Psilocybin 5 mg, Drug: Psilocybin 2 mg, Drug: PlaceboDose order: Psilocybin 2mg, Psilocybin 5mg, Placebo |
Who may qualify
- Ages
- 18 to 60 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (8 listed)
- 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
Key exclusion criteria (18 listed)
- 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
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Psilocybin 5 mgAlso: COMP360Partial Serotonin (5HT) 1A/2A Receptor Agonist Psilocybin | Drug | Placebo, Psilocybin_2, Psilocybin_5, Psilocybin_2, Placebo, Psilocybin_5, Psilocybin_2, Psilocybin_5, Placebo |
| Psilocybin 2 mgAlso: COMP360Partial Serotonin (5HT) 1A/2A Receptor Agonist Psilocybin | Drug | Placebo, Psilocybin_2, Psilocybin_5, Psilocybin_2, Placebo, Psilocybin_5, Psilocybin_2, Psilocybin_5, Placebo |
| PlaceboInactive placebo | Drug | Placebo, Psilocybin_2, Psilocybin_5, Psilocybin_2, Placebo, Psilocybin_5, Psilocybin_2, Psilocybin_5, Placebo |
Primary outcome
Brain activation and connectivity response to serotonergic stimulation as assessed by functional magnetic resonance imaging.
Time frame: Data collected on up to 3 visit days per participant.
Comparing whole brain blood-oxygen-level-dependent (BOLD) activation (institutional units) during the resting state in cases and controls when the serotonin system is activated by a single oral dose of psilocybin (COMP360) versus the placebo condition.
Brain electrophysiological activity task-free electroencephalography (EEG)
Time frame: Data collected on up to 3 visit days per participant.
Case-control comparison of task-free EEG by time-frequency analysis during placebo and when serotonin system is activated with psilocybin.
Brain electrophysiological activity electroencephalography (EEG) during visual stimulation
Time frame: Data collected on up to 3 visit days per participant.
Case-control comparison of EEG Evoked Potentials in response to visual stimulation during placebo and when serotonin system is activated with psilocybin.
Brain electrophysiological activity electroencephalography (EEG) during auditory stimulation
Time frame: Data collected on up to 3 visit days per participant.
Case-control comparison of EEG Event Related Potentials in response to auditory tones during placebo and when serotonin system is activated with psilocybin.
1 secondary outcome
Brain excitation and inhibition response to serotonergic stimulation as assessed by magnetic resonance spectroscopy.
Time frame: Data collected on up to 3 visit days per participant.
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 28 Jul 2025.
- Derived from this study: PubMed 38658877Whelan TP, Daly E, Puts NA, Smith P, Allison C, Baron-Cohen S, Malievskaia E, Murphy DGM, McAlonan GM. The 'PSILAUT' protocol: an experimental medicine study of autistic differences in the function of brain serotonin targets of psilocybin. BMC Psychiatry. 2024 Apr 25;24(1):319. doi: 10.1186/s12888-024-05768-2.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Psilocybin 5 mg and Psilocybin 2 mg in people with Autism Spectrum Disorder, run by King's College London at 1 site in United Kingdom.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 8 inclusion and 18 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 28 Jul 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United Kingdom. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Brain activation and connectivity response to serotonergic stimulation as assessed by functional magnetic resonance imaging. (time frame: Data collected on up to 3 visit days per participant.). The study lists 4 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT05651126, which also lists 1 linked publication.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 28 Jul 2025; AzTrials last refreshed its copy on 7 Nov 2026.