Study to Determine the Safety, Tolerability, and Efficacy of Evenamide in Patients With Chronic Schizophrenia

Inclusion Criteria: Demographics * Age - 18 years, or older * Sex - male, or non-childbearing potential female unless practicing adequate contraception Psychiatric * Has a current diagnosis of schizophrenia in accordance with DSM-5. * Has been treated with antipsychotics for at least 2 years. * Has a total score on the PANSS \< 80. * Has a Clinical Global Impression - Severity of disease (CGI-S) rating of mildly, moderately or moderately severely ill (score of 3, 4 or 5). * Needs antipsychotic treatment and is currently receiving a stable dose (minimally for 4 weeks prior to screening) of aripiprazole, clozapine, quetiapine, olanzapine, paliperidone, or risperidone (at least 2 mg risperidone dose-equivalent) * Current symptoms have been stably present for at least one month Procedural * Patient resides at home or in a residential care facility * If taking clozapine, patient agrees to blood monitoring Exclusion Criteria: Psychiatric * Severity of current episode of psychosis requires that the patient be hospitalized. Patients who are chronically hospitalized or in psychiatric day-care, whose hospitalization is for logistic reasons and not due to the severity of their illness, will be eligible for the study. * Severity of psychosis is rated severe or higher (CGI-S of 6 or greater). * Known suicidal risk. A "yes" response on the C-SSRS Suicidal Ideation Item 4 or Item 5, or a "yes" response on any of the five C-SSRS Suicidal Behavior items, at screening, or a suicide at…