Condition category
Mental and Behavioural Disorders
Date applied
Date assigned
Last edited
Retrospectively registered
Overall trial status
Recruitment status
No longer recruiting
Publication status

Plain English Summary

Background and study aims
Depression affects people in different ways and can cause a wide variety of symptoms. They range from lasting feelings of sadness and hopelessness (low mood), to feeling very tearful at unexpected moments (emotional lability). Many people with depression also have symptoms of anxiety. Treatment for depression involves either medication or talking treatments, but these do not work for everybody because some people have depression that is treatment-resistant. Psilocybin is a hallucinogenic drug that comes from what is often called ‘magic mushrooms’. The drug can put some people in a euphoric mood for a number of hours and reduce anxiety. Psilocybin has been given to healthy volunteers and to patients suffering from Obsessive Compulsive Disorder (OCD) and anxiety before with positive results, but it has not been tested in depression. The aim of this initial study is to investigate how this drug works on patients with treatment-resistant depression. We also want to find out which dose gives predictable results in improving peoples’ mood.

Who can participate?
Patients referred from local London psychiatric teams.

What does the study involve?
The potential psychological effects of psilocybin are fully described to all patients before they sign up for the study. Participants are made to feel very prepared for their experience before taking the drug and are taught ways to relax to reduce anxiety and promote a positive drug experience. Patients receive a low dose in the first session so that they have a first impression of the drug experience before moving on to a higher dose. People can respond to the drug very differently from one another and some may not want to take the higher dose. A positive environment is created during the study so that participants feel relaxed and don’t feel worried. The study team has a psychiatrist and psychotherapist and all dosing sessions are supervised by a medical doctor. Follow-up meetings take place after each dosing session and any bad feelings experienced by participants will be managed by the study psychiatrist, GPs and/or community mental health professionals.

What are the possible benefits and risks of participating?
Bad side effects are rare when psilocybin is taken by healthy volunteers but they may be more likely in vulnerable patients such as those with depression. Risks include anxiety, ‘bad trips’ (dysphoria) and rarer psychotic responses. We will minimise risks by excluding patients experiencing psychotic symptoms at the time of the study, or those who have a personal/family history of psychosis. The occurrence of negative feelings experienced by people taking psilocybin depends on the dose amount so the maximum dose we give is considered moderate in healthy volunteers.

Where is the study run from?
Imperial Clinical Research Facility, Hammersmith Hospital (UK)

When is the study starting and how long is it expected to run for?
April 2015 to December 2015

Who is funding the study?
Medical Research Council (UK)

Who is the main contact?
Dr R Carhart-Harris (UK)

Trial website

Contact information



Primary contact

Dr Robin Carhart-Harris


Contact details

Burlington Danes Building
Du Cane Rd
W10 5NA
United Kingdom

Additional identifiers

EudraCT number

2013-003196-35 number

Protocol/serial number

Version 7

Study information

Scientific title

Assessing the subjective intensity of oral PSILOcybin in patients with treatment-resistant DEPression: a PILOT study



Study hypothesis

Psilocybin will reduce symptoms of depression in patients diagnosed with treatment-resistant depression.

Ethics approval

NRES London West London, 03/09/2014, ref: 13/LO/1224

Study design

Open label design

Primary study design


Secondary study design

Non randomised study

Trial setting


Trial type


Patient information sheet

Not available in web format, please use the contact details to request a patient information sheet


Major depression


Two doses of psilocybin 10mg and 25mg per so, separated by one week

Intervention type



Phase II

Drug names


Primary outcome measure

Quick Inventory of Depressive Symptoms (QIDS) questionnaire at start of trial, then one day and one week post-psilocybin. QIDS is a self-report measure of depressive symptoms

Secondary outcome measures

1. Beck Depression Inventory (BDI) questionnaire
2. Hamilton Depression Rating Scale (HAM-D) questionnaire
3. Montgomery–Åsberg Depression Rating Scale (MADRS) questionnaire

Overall trial start date


Overall trial end date


Reason abandoned (if study stopped)


Participant inclusion criteria

1. Major depression of a moderate to severe degree (17+ on the 21-item HAM-D)
2. No improvement despite two courses of antidepressant treatment for adequate duration (6 weeks minimum) within current episode
3. No magnetic resonance imaging (MRI) contraindications

Participant type


Age group




Target number of participants


Participant exclusion criteria

1. Current or previously diagnosed psychotic disorder
2. Immediate family member with a diagnosed psychotic disorder
3. Medically significant condition rendering unsuitability for the study (e.g., diabetes, epilepsy, severe cardiovascular disease, hepatic or renal failure etc)
4. History of suicide attempts
5. History of mania
6. Blood or needle phobia
7. Positive pregnancy test at screening or during the study
8. Current drug or alcohol dependence
9. Allergy to gelatine or lactose
10. Lack of appropriate use of contraception
11. Breastfeeding

Recruitment start date


Recruitment end date



Countries of recruitment

United Kingdom

Trial participating centre

Imperial Clinical Research Facility
Hammersmith Hospital
W10 5NA
United Kingdom

Sponsor information


Imperial College London

Sponsor details

Burlington Danes Building
Du Cane Rd
W10 5NA
United Kingdom

Sponsor type




Funder type

Research council

Funder name

Medical Research Council

Alternative name(s)


Funding Body Type

government organisation

Funding Body Subtype

National government


United Kingdom

Results and Publications

Publication and dissemination plan

We intend to analyse the results with a view to publication in peer-reviewed scientific press. The first study report will be prepared after 01/12/2015.

Intention to publish date


Participant level data

Stored in repository

Basic results (scientific)

Publication list

2016 results in:
2017 results in:
2018 results in

Publication citations

Additional files

Editorial Notes

14/02/2018: Publication references added. 24/05/2016: Publication reference added. The registration was initiated on 30/03/2015 and finalised on 07/07/2015. The recruitment started on 21/04/2015, after initiation of public registration.