A Trial of the Efficacy and Safety of SEP-363856 in Acutely Psychotic Participants With Schizophrenia

Key Inclusion Criteria: * Male or female participants between 18 to 65 years of age (inclusive) at the time of consent. * Participant has an identified reliable informant (eg, caregiver, relative, friend, case worker, residential treatment staff). * Participant is experiencing an acute exacerbation or relapse of symptoms, with onset ≤ 2 months prior to screening 1. The participant requires hospitalization for this acute exacerbation or relapse of symptoms. 2. If already an inpatient at screening, has been hospitalized for less than 2 weeks for the current exacerbation at the time of screening. * Participants who are experiencing an acute exacerbation of psychotic symptoms and marked deterioration of usual function as demonstrated by meeting ALL of the following criteria at the screening and baseline visits: 1. Participant must have a PANSS total score ≥ 80 AND 2. Participant must have a CGI-S score ≥ 4. * Participants who have received previous outpatient antipsychotic treatment at an adequate dose (minimal recommended dose for the treatment of schizophrenia according to the manufacturer labeling) for an adequate duration (at least 6 weeks) and who showed a previous good response. Key Exclusion Criteria: * Sexually active participants or persons of childbearing potential who do not agree to practice 2 different clinical trial sponsor approved methods of birth control or remain abstinent during the course of the trial and for 30 days after the last dose of study drug. * Participant has a current DSM-5 diagnosis or presence of symptoms consistent with a DSM-5 diagnosis other than schizophrenia. * Participant has had psychiatric hospitalization(s) for more than 30 days (cumulative) during the 90 days prior to screening. * Participant has previously received SEP-363856 or was previously enrolled in a SEP-363856 clinical study