The drug being tested in this study is called TAK-041. TAK-041 is being tested to evaluate its safety, tolerability, and PK of single and multiple doses in healthy participants and as add-on therapy to antipsychotics in participants with stable schizophrenia. This study will also assess the oral bioavailability in healthy participants administered with tablet formulation compared to oral suspension formulation in fasted state, and effect of high-fat, high-calorie meal on the PK of single dose of TAK-041 tablet formulation.~The study will enroll approximately 114 participants. The study is composed of 4 parts. Part 1 (single-rising dose [SRD], alternating panel design and a sequential panel design), Part 2 (multiple-rising dose [MRD], sequential panel design), Part 3 (open label parallel design), and Part 4 (single dose cohort).~Part 1 consists of 5 cohorts, participants in Cohorts 1 and 2 will be randomly assigned (by chance, like flipping a coin) to treatment sequences of 2 periods and for Cohorts 3 to 5 participants will be assigned to a single dose sequential-panel:~TAK-041 5-160 mg~Placebo (inactive) - this is a similar formulation that looks like the study drug but has no active ingredient.~Part 2 consists of 4 cohorts, participants will be randomly assigned to one of the two treatments:~TAK-041~Placebo Dose levels for Part 2 cohort 1 will be based on emerging safety/tolerability and PK data from Part 1. The dose levels for Part 2 Cohorts 2 onwards will be based on emerging safety/tolerability and available PK data from Part 1 and from preceding cohorts in Part 2.~Part 3 consists of 2 cohorts, participants will be randomly assigned to one of the two treatments under fasted state or fed state:~TAK-041 40 mg tablet (Fasted state)~TAK-041 40 mg tablet (Fed state)~Part 4 consists of 1 cohort, participants will be randomly assigned to one of the two treatments:~TAK-041~Placebo The dose levels for Part 4 will be based upon the emerging safety/tolerability and PK data of same dose in healthy participants from Part 2.~This single center trial will be conducted in the United States. Participants will remain confined to the study site from check-in (Day -1) through Days 5 of each period in Part 1, on Days -2 to 3, Days 7 to 10, Days 14 to 17, Day 21 to 24 in Part 2, on Days 1 to 3 in Part 3, and on Days -2 to 3, Days 7 to 10, Days 14 to 17, Days 21 to 24 in Part 4. A final visit that completes the study will occur 12 to 16 days after the last safety and PK follow-up visit in Part 1, 2 and 4, and 18 days after dosing in Part 3.
The purpose of this study is to evaluate the safety, tolerability, and pharmacokinetics (PK) of TAK-041:~Following oral single and multiple doses in healthy participants.~As add-on therapy to antipsychotics in stable schizophrenia participants.~To determine the oral bioavailability of the TAK-041 tablet formulation compared to the oral suspension formulation in the fasted state.~To assess the effect of food on the PK of TAK-041 in healthy participants.