Background: The evidence for safe and effective interventions to treat the negative and cognitive symptoms of schizophrenia is lacking. Objectives: Vortioxetine is a novel antidepressant that has been used as adjunctive therapy for the treatment of psychosis; however, its effectiveness in clinical practice is relatively unknown. In this study, we aimed to determine the potential clinical effectiveness and safety and tolerability of vortioxetine in psychosis. Design: This is a non-interventional, retrospective study on the add-on use of vortioxetine in a group of people with schizophrenia-spectrum disorders in a large UK NHS mental health trust. Methods: Clinical effectiveness of vortioxetine was retrospectively assessed through the Clinical Global Impression – Severity (CGI-S) scale at 3 months. Safety and tolerability were evaluated through treatment discontinuation rates at 3, 6, and 12 months, and clinical reasons were evaluated at the primary endpoint of 3 months. Results: Data were available for 40 subjects with a diagnosis of schizophrenia or schizoaffective disorder–prescribed vortioxetine treatment; 30 (75%) remained on treatment at 3 months. At CGI-S assessment, 15 of the 35 evaluated subjects reported at least a 1-point improvement, from 5 at baseline to 4 after 3 months of treatment. Twenty-six (65%) remained on treatment at 1-year follow-up. The main reasons for those discontinuing treatment were inadequate response (10%) and manic switch (7.5%), while one subject refused treatment. Tolerability to treatment was good, and 36 subjects (90%) reported no adverse events specific to vortioxetine treatment. Conclusion: Schizophrenia is a complex illness, and there is insufficient treatment response in many individuals. A significant proportion of whom may require adjunctive treatments depending on the nature of the residual symptoms. Vortioxetine could be a potentially safe and effective option in such people, but further controlled studies are required.