The purpose of this study is to investigate the effect of Lu AF35700 on electrical activity in the heart as measured on an electrocardiogram (ECG) in patients with schizophrenia or schizoaffective disorder after 6 weeks of treatment

Inclusion Criteria:

• The patient is able by her/himself to provide informed consent to participate in the study
• The patient has a primary diagnosis of schizophrenia or schizoaffective disorder (DSM-5™ criteria)
• The patient has BMI ≤35 kg/m2
• The patient has a Clinical Global Impression - Severity of Illness (CGI-S) score ≤4 (moderately ill)
• PANSS total score ≤ 80 and a score ≤4 (moderate) on the PANSS items, P7 (hostility) and G8 (uncooperativeness)
• The patient is willing to be hospitalized for up to 8 weeks
• The patient is generally healthy based on medical history, physical examination, vital signs, ECG, and laboratory tests.
• The patient agrees to protocol-defined use of effective contraception

Exclusion Criteria:´

• The patient experienced acute exacerbation of psychosis requiring hospitalization within the last 3 months or required change in medication due to exacerbation of psychosis within the last 8 weeks
• The patient has met moderate or severe co-morbid Substance Abuse Disorder DSM-5™ criteria in the last 3 months
• The patient is at significant risk of harming her/himself or others in the opinion of the investigator or according to Columbia Suicide Severity Rating Scale (C-SSRS)
• The patient has tested positive for human immunodeficiency virus (HIV), hepatitis B surface antigen (HBsAg), or hepatitis C virus antibody (anti-HCV)

Other protocol defined inclusion and exclusion criteria may apply