NCT04630964

Who might be able to join this trial:

• You are between 20 and 65 years old at the time of signing the consent form
• You can read, speak, and understand Swedish
• You are willing and able to follow all study requirements, including attending all visits and completing all evaluations
• You are able to swallow capsules
• If you are a woman who could become pregnant, you agree to use effective birth control throughout the study, from the screening visit through the Day 42 check-in
• You have been diagnosed with major depressive disorder (a serious form of depression that comes and goes) and are currently going through a depressive episode that has lasted at least 30 days but less than 5 years
• Your depression symptoms are rated as moderate to severe based on standardised questionnaire scores at both the screening and baseline visits
• You have a trusted person (a "support person") who can take you home or to a safe place after you receive the study treatment

Who may not be able to join:

• You are pregnant, plan to become pregnant during the study, or are currently breastfeeding
• Your current depressive episode has been going on for more than 5 years
• You are unwilling or unable to stop formal psychotherapy during the study
• You are currently taking antidepressant medication
• During your current depressive episode, you have already received deep brain stimulation (DBS) or vagus nerve stimulation (VNS) — two specialist procedures sometimes used for depression
• You are currently receiving electroconvulsive therapy (ECT) or transcranial magnetic stimulation (TMS) — other specialist treatments for depression
• You are taking certain medications that affect how the body processes drugs (called UGT enzyme modulators, such as valproate) and are unwilling or unable to stop taking them (confirm with trial site for full list)
• You have ever used psychedelic substances, including psilocybin, LSD, mescaline, DMT, ayahuasca, MDMA, ibogaine, or similar substances
• You have certain heart or cardiovascular conditions, such as coronary artery disease, heart failure, a previous heart attack, an abnormal heart rhythm, an artificial heart valve, or other significant heart conditions (confirm with trial site for full list)
• Your blood pressure is too high at the screening or baseline visits, based on specific measurements taken three times
• You have a history of stroke or mini-stroke (also called a transient ischemic attack or TIA)
• You have moderate or severe liver disease
• You have epilepsy
• You have insulin-dependent diabetes, or you take diabetes tablets and have previously needed medical help due to low blood sugar
• You are unwilling or unable to stop taking certain medications before dosing, including Viagra (sildenafil), tadalafil, or similar drugs at least 72 hours before the treatment day, or high-dose niacin supplements for the duration of the study
• Your urine drug test comes back positive for certain substances, including amphetamines, cocaine, cannabis, opiates, MDMA, or others — with limited exceptions for some prescribed medications (confirm with trial site)
• You are so dependent on nicotine that you would be unable to go without it for the 7–10 hours of the dosing session
• You have been diagnosed with schizophrenia or related conditions, depression with psychotic features, or bipolar disorder (type I, II, or unspecified)
• You have been diagnosed with antisocial personality disorder
• You have a moderate or severe alcohol or drug use disorder (other than caffeine), or have had such a diagnosis in the past 12 months
• You have another psychiatric condition that the study doctor considers more serious or more important to treat than your depression
• A close blood relative (parent, sibling, or child) has been diagnosed with schizophrenia or a related condition, or with Bipolar I Disorder
• You have a psychiatric condition that the study team believes would make it unsafe or unsuitable for you to take psilocybin or to build a working relationship with the study facilitators
• You have reported serious thoughts of suicide or self-harm, including specific scores on a depression questionnaire at screening or baseline, or at any point before joining the study
• You have any physical or mental health symptom, or are taking any medication, that the study doctors believe would make participation unsafe or unsuitable
• You have a known allergy or intolerance to any ingredient in the study