Rapid antidepressant effect of S-ketamine in schizophrenia

Introduction

Post-psychotic depression (ICD-10: F20.4) is described as a common but often neglected complication of schizophrenia, affecting up to 36% of patients and carrying substantial clinical need for new treatment options. Earlier research has repeatedly documented rapid antidepressant and anti‑suicidal effects of ketamine in unipolar and bipolar depression, and some studies reported benefit in depressed patients with a history of psychotic symptoms. Despite this, ketamine has been largely avoided in primary psychotic disorders because of a theoretical risk of provoking dissociative or psychotic symptoms, leaving its clinical effects in schizophrenia poorly characterised. This paper reports a single case intended to document the feasibility, tolerability and clinical outcome of intravenous S‑ketamine augmentation in a patient with schizophrenia who developed a severe post‑psychotic depression with suicidal ideation. The authors aim to show whether S‑ketamine can produce rapid antidepressant and anti‑suicidal effects in this diagnostic context without provoking meaningful psychotic or dissociative phenomena, and to prompt further research on ketamine use in psychotic disorders.