 The negative symptoms of schizophrenia represent an important dimension of psychopathology, and reflect the absence or diminution of normal behaviours and functions. They include deficiencies in emotional responsiveness, drive, and emotional and social engagement. Persistent negative symptoms are held to account for much of the long-term morbidity and poor functional outcome in patients with established schizophrenia, but if they prove resistant to antipsychotic medication there is a very limited evidence base regarding specific treatments. The aim of this double-blind, placebo-controlled trial is to establish the clinical and cost effectiveness of an SSRI antidepressant, citalopram, in the management of negative symptoms of schizophrenia over a year. The study sample will be adults with a diagnosis of schizophrenia, clinically stable for 3 months with a consistent antipsychotic regimen, and characterised by persistent negative symptoms to a criterion level of severity. 