Interventions
In Part A, to assess the safety, tolerability, and PKs of single‐dose zuranolone, a single 10‐, 20‐, or 30‐mg dose of zuranolone or placebo in capsule form was administered orally after a standard breakfast meal on Day 1 of the trial. To evaluate the effects of multiple doses, seven consecutive daily doses of zuranolone or placebo were administered orally on Days 4–10 of the trial after a standard dinner meal. Japanese adults were administered zuranolone 10, 20, or 30 mg; White adults were administered zuranolone 20 or 30 mg; and Japanese elderly were administered zuranolone 30 mg. In Part B, to assess the effects of food on PKs and safety, a single dose of zuranolone 30 mg was administered orally in the fast (food intake was prohibited for 10 h before and 4 h after drug administration) or fed state (30 min after a high‐fat breakfast meal) on Day 1 and Day 9 of the study in a crossover design. In Part C, to assess EEG changes, a single dose of zuranolone 10 or 30 mg was administered orally in the fed state with a standard meal on Days 1, 9, and 17 of the study. Subjects were randomized into one of three groups based on a 3 × 3 Latin square design. A single dose of zuranolone 10 or 30 mg or placebo was administered in a predetermined order depending on the assigned group.