A Study to Assess the Effect of Seltorexant Compared to Placebo on Respiration During Sleep in Adult Participants With Obstructive Sleep Apnea

Inclusion Criteria

• •Participant must be a women of non-childbearing potential (WONCBP) or man. A WONCBP is defined as: a) Postmenopausal (postmenopausal state is defined as no menses for 12 months without an alternative medical cause. A high follicle stimulating hormone (FSH) level in the postmenopausal range may be used to confirm a postmenopausal state in women not using hormonal contraception or hormonal replacement therapy; b) Permanently sterile (permanent sterilization methods include hysterectomy, bilateral salpingectomy, bilateral tubal occlusion/ligation procedures, and bilateral oophorectomy
• •Meet the International Classification of Sleep Disorder diagnostic criteria for obstructive sleep apnea (OSA) based on the investigator's assessment with or without sleep study. The OSA diagnosis can be confirmed by previous sleep studies, appropriate documentations (for example, medical records or letters from treating physicians) or documented conversation with the treating physician
• •Mild to moderate OSA, defined as AHI greater than or equal to (\>=)5 to less than (\<)30, based on screening polysomnography (PSG)
• •Body mass index (BMI) between 18 and 40 kilogram per meter square (kg/m\^2) (inclusive) (BMI = weight/height\^2)
• •Must be otherwise healthy based on physical examination, medical history, vital signs, 12-lead electrocardiogram (ECG), and clinical laboratory tests performed at screening. If there are abnormalities, they must be consistent with the underlying illness in the study population. If the results of the clinical laboratory tests are outside the normal reference ranges, the participant may be included only if the investigator judges the abnormalities from normal to be not clinically significant or to be appropriate and reasonable for the population under study