Microdosing lysergide (20 µg) to improve symptoms, emotion regulation and sleep in adults with ADHD

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What is this study about?

The study focuses on adults diagnosed with Attention Deficit Hyperactivity Disorder. It tests whether a very small oral dose (20 µg) of LSD, supplied as a solution and identified by the code name LYsergide, can affect symptoms. A matching placebo (1 mL of 95 % ethanol) is used for comparison.

The purpose is to determine if this microdose can improve core ADHD symptoms, help with emotional regulation, and enhance sleep.

Participants will receive either the study drug or the placebo each day for a set number of weeks. Throughout the trial, they will attend regular visits where simple questionnaires about attention, mood, and sleep are completed, and a brief blood sample is taken to assess the activity of the enzyme CYP2D6, which helps the body process medicines. Safety checks and brief assessments are performed to monitor any effects.

1 baseline assessment

you complete questionnaires that measure adhd symptoms, emotion regulation, and sleep quality.

a blood sample may be taken to evaluate the pharmacokinetic profile, which shows how the study drug moves through the body.

2 randomization

you are assigned to receive either the active medication or the control.

the active medication is lsd (lysergic acid diethylamide) provided as an oral solution containing a dose of 20 µg per administration.

the control is a 1 ml solution of 95 % ethanol, which contains no active drug.

3 medication administration

you take the assigned oral solution according to the schedule given by the study staff.

the microdosing regimen continues for the period defined by the study protocol.

4 symptom tracking

you regularly complete short questionnaires that record changes in adhd symptoms, emotion regulation, and sleep.

5 follow‑up visits

you attend scheduled visits where study personnel review your questionnaire responses.

additional blood samples may be collected to monitor the pharmacokinetic profile and other secondary measurements.

6 final assessment

you complete a final set of questionnaires covering adhd symptoms, emotion regulation, and sleep.

a final blood sample is taken to complete the pharmacokinetic and other secondary analyses.

7 study closure

all data are recorded and the participant’s involvement in the trial ends.

Who Can Join the Study?

Be able and willing to sign a written informed consent form before any study procedures and follow all study rules.
Have symptoms that match the official definition of ADHD in the DSM‑5 (a standard diagnostic manual), confirmed by a detailed interview called the SCID‑5 (a structured questionnaire used by clinicians).
Score 14 or higher on the Adult ADHD Self‑Report Scale (ASRS) screening questionnaire, which measures the severity of ADHD symptoms.
Not be taking any psychotropic medication (drugs that affect the brain), including medicines used for ADHD.
Agree not to use any illegal psychoactive substances (drugs that change mood or perception) during the study.
Agree to take the study pill once every third day for 6 weeks, and after each dose not drive a vehicle or operate heavy equipment for 6 hours; after three specific clinic visits, travel home by taxi, public transport, or with a caregiver.
Agree to avoid all alcoholic drinks from Monday through Friday, and on weekends limit alcohol to no more than 6 “standard drinks” (about a small glass of wine, a regular beer, or a shot of liquor).
Agree to limit smoking to no more than 10 cigarettes per day and coffee to no more than 2 cups per day for the entire 6‑week treatment period.
Understand what will happen in the study and the possible risks involved.
Be between 18 and 50 years old at the time of screening.
Have a normal body weight, measured as a body mass index (BMI) between 18 and 28 kg/m² (BMI is calculated from weight and height).

Who Cannot Join the Study?

Having a diagnosed psychotic disorder (such as schizophrenia) or bipolar disorder, or having a close family member (parent, sibling, or child) with one.
Having any heart problems, such as an irregular heartbeat (arrhythmia) or blocked arteries (ischemic heart disease).
Having ever tried to kill yourself, thought about it, or having current suicidal thoughts (within the past week).
Planning to start, stop, or change any medicines, vitamins, or supplements from the time you sign consent until the study ends.
Being likely to need admission to a psychiatric hospital during the study.
Being likely to need psychiatric medicines that could affect the study’s results or safety, within 6 weeks after the baseline visit.
Not willing or able to stop psychiatric medicines (such as SSRIs or ADHD medication) from baseline through the end of the study.
Using weight‑loss drugs within 21 days before screening or during the study.
Planning to start, stop, or change therapies such as psychotherapy, massage, meditation, acupuncture, hypnosis, yoga, or similar activities from consent until the study ends.
Using strong inhibitors of the liver enzyme CYP2D6, or moderate inhibitors if the investigator decides they are a problem.
Having used any psychedelic drug (such as psilocybin, LSD, mescaline, ayahuasca, DMT, or 5‑MeO‑DMT) in the past 6 months.
Having previously experienced serious side effects (like severe anxiety or panic attacks) from psychedelic drugs.
Having a positive urine drug test at screening or at any later lab visit.
Having an abnormal heart test (electrocardiogram (ECG)) such as uncontrolled atrial fibrillation or signs of reduced blood flow to the heart.
Having any other condition, treatment, lab abnormality, or situation that the medical supervisor believes makes participation unsafe or could affect the study results.
Being unwilling or unable to consume a very small amount of alcohol, because the study medication is mixed in 95% ethanol.
Having a past (more than 12 months ago) or current substance addiction or dependence, except for nicotine if you smoke no more than about 10 cigarettes per day.
Being a woman who can become pregnant and not willing or able to use a highly effective method of contraception for the whole study, or being a man who has sex with a woman who can become pregnant and not willing or able to use barrier methods (such as condoms) for the whole study.
Being currently pregnant, breastfeeding, or planning to become pregnant or breastfeed during the study.
Being a man who plans to donate sperm during the study.
Having serious body (somatic) disorders such as cancer that involves the central nervous system (CNS), severe heart disease, untreated high blood pressure, severe liver disease, or severely reduced kidney (renal) function.
Having high blood pressure (systolic over 140 mmHg or diastolic over 90 mmHg).

Where you can join this trial?

Verified and Recommended Sites

No sites found in this category

Verified Sites

Site Name	City	Country	Status
University Hospital Maastricht	Maastricht	The Netherlands

Other Sites

No sites found in this category

Trial status

Country	Status	Recruitment Start
The Netherlands	Not yet recruiting	01.06.2026

Trial locations

Investigated drugs:

LYSERGIDE

LSD is a serotonergic agent that is being given in a very small amount (microdose) taken by mouth as a liquid solution. In this study the researchers are testing whether taking this tiny dose can help adults with ADHD improve their main symptoms, better control their emotions, and have a more regular sleep pattern.

Investigated diseases:

Attention deficit hyperactivity disorder

Attention-Deficit/Hyperactivity Disorder (ADHD) – A neurodevelopmental condition marked by persistent patterns of inattention, hyperactivity, and impulsivity that are greater than typical for a person’s age. Symptoms often appear in childhood and can continue into adulthood, affecting daily tasks, work, and relationships. People with ADHD may find it difficult to stay focused, organize activities, or sit still for extended periods. Over time, the intensity of core symptoms may change, with some individuals experiencing more difficulty with attention and others with restlessness. The condition can also influence emotional regulation, leading to mood swings or frustration. Sleep patterns may be irregular, with some individuals experiencing trouble falling asleep or staying asleep.

Trial ID:

2025-520906-36-00

Protocol code:

P155

Trial Phase:

Therapeutic exploratory (Phase II)

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Microdosing lysergide (20 µg) to improve symptoms, emotion regulation and sleep in adults with ADHD

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