Pharmacokinetics of Zelquistinel in Fasted or Fed State

Inclusion Criteria: * Available for the entire study period; willing and able to comply with the protocol requirements and study restrictions, to remain at the CRU for the required duration of the study, and to return for the Follow-Up Visit * Male or female participants ≥18 to ≤59 years of age at Screening * Minimum body weight of at least 50.0 kg at Screening * Body mass index (BMI) 18.0 to 35.0 kg/m2, inclusive, at Screening * Able and willing to swallow whole tablets without breaking, cutting, or chewing * Non- or ex-smokers * Considered generally healthy in the opinion of an investigator upon completion of medical history, physical examination, vital sign measurements, Screening clinical laboratory test results, and Screening ECG * Female participants of childbearing potential must use an acceptable method of contraception, including hormonal contraceptives, abstinence from heterosexual intercourse, intrauterine device with or without hormones, or double-barrier method (eg, condom and spermicide) for 30 days before Screening, during the study, and for 30 days after the last administration of study drug * Female participants of nonchildbearing potential should be surgically sterile (ie, have undergone complete hysterectomy, bilateral salpingectomy, bilateral oophorectomy, or tubal ligation/occlusion) or in a menopausal state (at least 1 year without menses) * Male participants must agree to use a double-barrier method (condom and spermicide) or remain abstinent from heterosexual intercourse at the time of Screening, during the study, and for 90 days after the last administration of study drug * Male participants must agree not to donate sperm during the study and for 90 days after the last administration of study drug * Able to fully consume the required fed meal within 30 minutes without substitutions * Willing and able to provide written informed consent to participate in the study, is able to understand the procedures and study requirements, and agrees to comply with all required study requests and procedures * Able to speak, read, and understand English sufficiently to allow completion of all study assessments Exclusion Criteria: * Female participant who is currently pregnant or lactating or is planning to become pregnant during the study * Positive pregnancy test at Screening or on Day -1 * Positive test results for HIV 1/2 Ag/Ab, hepatitis B surface antigen (HBsAg), hepatitis C virus antibody (HCV Ab) at Screening * Positive urine screen for drugs or alcohol at Screening or on Day -1 * Clinically significant history or evidence of gastrointestinal (excluding cholecystectomy), hepatic, renal, endocrine, pulmonary, neurologic, psychiatric, cardiovascular, hematologic, dermatologic, immunologic, or metabolic disease; or any other condition or organ system disease known to interfere with the absorption, distribution, metabolism, or elimination of drugs that in the opinion of an investigator would jeopardize the safety of the participant or impact validity of study results. * Current or history of alcohol or substance abuse, with the exception of being fully recovered with no use of alcohol or substances of abuse within the 12 months before Screening * Any clinically significant illness in the previous 30 days before Screening or Day -1 * Malignancy, a history of malignancy, or has received treatment for a malignancy at any time, with the exception of resected and cured basal cell carcinoma and squamous cell carcinoma of the skin (\>1 year) * Poor venous access * Any medical condition(s) considered by an investigator to be clinically significant for study participation * Supine pulse rate \<60 or ≥100 bpm at Screening or on Day -1 * Donation or significant loss of blood products of 500 mL or more within 56 days before Screening, or donation or loss of plasma within 7 days before Screening * Suicidal behavior or suicidal ideation of score 4 (active suicidal ideation with some intent to act without specific plan) or score 5 (active suicidal ideation with specific plan and intent) based on the C-SSRS within 12 months before Screening; a history of suicide attempt in the last 6 months; or more than 1 lifetime suicide attempt * Positive responses on the CADSS or BPRS+ assessments at Screening, indicating evidence of dissociative symptoms or psychosis, as determined by the investigator * Unable to abstain from consumption of grapefruit or Seville oranges or their juices from 14 days before the first administration of study drug until collection of the final PK sample * Unable to abstain from caffeine- or xanthine-containing products (eg, coffee, tea, cola drinks, and chocolate) for 24 hours before admission to the clinical research unit until discharge * Unable to abstain from alcohol for 48 hours before admission to the clinical research until discharge * Unable to abstain from strenuous exercise for 48 hours before admission to the clincal research unit until after the collection of the final PK sample * A marked prolongation of QT/corrected QT interval (QTc), defined as repeated QTc * \>450 ms for male participants and \>470 ms for female participants using QT interval corrected for heart rate using Fridericia's formula (QTcF), at Screening or on Day -1 * Presence of observed abnormality (evidenced from physical examination, ECG \[PR interval \>220 ms, QRS \>110 ms QRS or T wave morphology that in an investigator's opinion renders QT interval assessment unreliable\], vital sign measurements, or clinical laboratory test results) considered by an investigator to be clinically significant for study participation. Out-of-range values can be repeated to confirm if the abnormality is sustained * Use of any prescription medication (including oral contraceptives) within 14 days before Screening and/or use of any over-the-counter medications (such as antacids, vitamins, minerals, dietary/herbal preparations, and nutritional supplements) within 7 days before Screening * Allergy to NMDA receptor drugs, to any component of the dosage form, or any other allergy, which, in the opinion of an investigator, contraindicates their participation * Treatment with any investigational drug within 30 days or 5 half-lives of the drug (whichever is longer) before Screening * Contraindications to lumbar puncture for CSF collection: * Skin infection near the site of the lumbar puncture * Significant scarring near the site (tattoos are acceptable) * Uncorrected bleeding disorders * Acute spinal cord trauma * Suspicion of increased intracranial pressure due to a mass in the brain * Significant degenerative changes or scoliosis of the lumbar spine * Any reason that, in the opinion of the investigator, would prevent participation in the study