A Single-Dose Positron Emission Tomography (PET) Study to Determine the Effect of TAK-041 on Amphetamine-Induced Dopamine Release in the Central Nervous System (CNS)

The drug being tested in this study is called TAK-041. This study will look at brain penetration of single oral doses of TAK-041 and its effects on amphetamine-induced dopamine release in the CNS.

The study will enroll participants until 12 evaluable participants complete all study procedures. The first 4 participants enrolled in this study will receive a dose of 20 mg TAK-041 and 0.50 milligram per kilogram (mg/kg) dose of amphetamine. The dose for subsequent participants will be determined based on the results of amphetamine-induced dopamine release in the first 4 participants (5 to 40 for TAK-041 and 0.25 or 0.50 mg/kg for the amphetamine).

This single-center trial will be conducted in the United Kingdom. The overall time to participate in this study is approximately 92 days. Participants will remain confined to the clinic for 3 to 4 days during 2 confinement periods. Participants will make monthly visits during Days 8-64 and a final visit 30 days later.

Inclusion criteria

• Is in good health as determined by physical examination, electrocardiogram (ECG), and laboratory evaluations.
• Weighs at least 45 kilogram (kg) and has a body mass index (BMI) from 18.0 to 30.0 kilogram per square meter (kg/m^2), inclusive, at Screening.

Exclusion criteria

• Has a history of drug abuse (defined as any illicit drug use) or a history of alcohol abuse (defined as regular consumption of more than 21 units per week) within 1 year prior to the Screening Visit or is unwilling to agree to abstain from alcohol and drugs throughout the study. One unit is equivalent to 8 grams of pure alcohol, which is equivalent to 10 milliliter (mL) of pure ethanol (alcohol) or approximately a half-pint of beer, 1 measure of spirits, or 1 glass of wine.
• Has used nicotine-containing products (including but not limited to cigarettes, pipes, cigars, chewing tobacco, nicotine patch or nicotine gum) within 28 days prior to Check-in on Day -1. Cotinine test is positive at Screening or Check-in (Day -1).
• Has poor peripheral venous access.
• Has donated or lost 450 mL or more of his blood volume (including plasmapheresis), or had a transfusion of any blood product within 90 days prior to Confinement Period 1.
• Has had previous research-related exposure to ionizing radiation such that, in combination with the exposure from this study, their exposure will be greater than (>)10 millisievert (mSv) for the previous year.
• Has a contraindication to magnetic resonance imaging (MRI) based on the standard MRI screening questionnaire. Contraindications include ferromagnetic foreign bodies (example, shrapnel, ferromagnetic fragments in the orbital area), certain implanted medical devices (example, aneurysm clips, cardiac pacemakers), or claustrophobia.
• Has findings on the screening brain MRI scan that will potentially compromise participant safety or the scientific integrity of the study data if the participant were to participate in this study.