A Study Assessing the Safety, Tolerability, and Pharmacokinetics of SEP-363856 in Male and Female Subjects With Schizophrenia

This is a single-center, randomized, single-blind, placebo-controlled, ascending single oral dose study designed to evaluate the safety, tolerability, and PK of SEP-363856 and its metabolite SEP-363854 in male and female subjects with schizophrenia. This study will determine the maximum-tolerated dose (MTD) for a single oral dose of SEP-363856, and characterize the plasma PK profiles of SEP-363856 and its metabolite SEP-363854 in male and female subjects with schizophrenia. For each of the dose-escalation cohorts, 12 subjects (9 active subjects and 3 placebo subjects) will receive a single oral dose. An attempt will be made to have at least one-third of subjects in each cohort be female. Each cohort will be comprised of 12 subjects (9 active, 3 placebo). Within each cohort, subjects will be randomized to receive either SEP-363856 (active) or matched placebo in a 3:1 ratio. The planned dose levels that will be evaluated are: * Cohort 1: A single oral 25 mg dose of SEP-363856 or matched placebo. * Cohort 2: A single oral 50 mg dose of SEP-363856 or matched placebo. * Cohort 3: A single oral 100 mg dose of SEP-363856 or matched placebo. * Cohort 4: A single oral 150 mg dose of SEP-363856 or matched placebo.