Study to Evaluate the Respiratory Safety of Lemborexant in Adult and Elderly Healthy Subjects and Adult and Elderly Subjects With Mild Obstructive Sleep Apnea

HV: Lemborexant-matched oral placebo will be administered at bedtime in the clinic (within 5 minutes of lights off).

HV: 10 mg oral lemborexant will be administered at bedtime in the clinic (within 5 minutes of lights off).

HV: 25 mg oral lemborexant will be administered at bedtime in the clinic (within 5 minutes of lights off).

OSA: Lemborexant-matched oral placebo will be administered at bedtime in the clinic (within 5 minutes of lights off) in the evening of Days 1 and 8. On Days 2 to 7, participants will take study drug at home, immediately (within 5 minutes) of the time they intend to try to sleep.

OSA: 10 mg oral lemborexant will be administered at bedtime in the clinic (within 5 minutes of lights off) in the evening of Days 1 and 8. On Days 2 to 7, participants will take study drug at home, immediately (within 5 minutes) of the time they intend to try to sleep.