The purpose of this study is to evaluate the safety and tolerability of TAK-418 following single oral doses in healthy participants.

The drug being tested in this study is called TAK-418. TAK-418 is being tested in healthy participants in order to evaluate the safety, tolerability, and pharmacokinetics (PK) of single oral doses.

The study will enroll approximately 40 healthy participants. The study consists of equally divided 5 sequential cohorts of 8 participants each. In each of the following cohorts, 6 participants will be randomized to receive TAK-418 and 2 participants will receive matching placebo-which will remain undisclosed to the participant and study doctor during the study (unless there is an urgent medical need):

• Cohort 1: TAK-418 5 mg
• Cohort 2: TAK-418 15 mg
• Cohort 3: TAK-418 30 mg Fasted + TAK-418 30 mg Fed
• Cohort 4: TAK-418 40 mg
• Cohort 5: TAK-418 60 mg

All participants will be asked to take TAK-418 or placebo-matching capsule once on Day 1 in each cohort. A washout period of 28-days will be maintained between the doses in Cohort 3.

This single center trial will be conducted in the United States. Participants in this study will be assigned to one of 5 possible dose cohorts. Male participants will return for additional outpatient visits on Days 91 and 93 (+/- 7 days) and may return for outpatient visits on Days 182 and 184 (+/- 7 days) (depending on results from the Day 93 Visit).

Inclusion Criteria:

1. Is a male or female participants with a body mass index (BMI) within the range of 18.5 -30.0 kilogram per square meter (kg/m^2) at the Screening Visit.

2. Is a nonsmoker who has not used tobacco or nicotine-containing products (example, nicotine patch) for at least 6 months before trial drug administration of the initial dose of trial drug or invasive procedure.

3. Must be judged to be in good health by the investigator, based on clinical evaluations including laboratory safety tests, medical history, physical examination, 12-lead ECG, and vital sign measurements performed at the Screening Visit and before administration of the initial dose of trial drug or invasive procedure as per principal investigator's judgment.

4. Female subjects with no childbearing potential, defined by at least 1 of the following criteria:

   • Postmenopausal (defined as 12 months of spontaneous amenorrhea in women aged greater than [>]45 years, 6 months of spontaneous amenorrhea in women aged >45 years with serum follicle-stimulating hormone [FSH] levels >40 milli-international units per milliliter [mIU/mL]). Appropriate documentation of FSH levels is required.
   • Surgically sterile by hysterectomy and/or bilateral oophorectomy with appropriate documentation of surgical procedure.
   • Had a tubal ligation with appropriate documentation of surgical procedure.
   • Has a congenital condition resulting in no uterus.

Exclusion Criteria:

1. Has had major surgery, donated or lost 1 unit of blood (approximately 500 milliliter [mL]) within 4 weeks before the Screening Visit.
2. Has a risk of suicide according to the investigator's clinical judgment per the Columbia-Suicide Severity Rating Scale at Screening or has made a suicide attempt in the 6 months before Screening.

Takeda makes patient-level, de-identified data sets and associated documents available after applicable marketing approvals and commercial availability have been received, an opportunity for the primary publication of the research has been allowed, and other criteria have been met as set forth in Takeda's Data Sharing Policy (see www.TakedaClinicalTrials.com/Approach for details). To obtain access, researchers must submit a legitimate academic research proposal for adjudication by an independent review panel, who will review the scientific merit of the research and the requestor's qualifications and conflict of interest that can result in potential bias. Once approved, qualified researchers who sign a data sharing agreement are provided access to these data in a secure research environment.

The safety analysis set included all randomized participants who received at least 1 dose of study drug.

Treatment-emergent adverse events are adverse events that started after the first dose of the study drug up to Day 184

At each visit the investigator had to document any occurrence of adverse events and abnormal laboratory findings. Any event spontaneously reported by the participant or observed by the investigator was recorded, irrespective of the relation to study treatment.