Main objective: To assess the efficacy of two antidepressants of different pharmacological families: citalopram (Selective serotonin reuptake inhibitors, SSRI) and reboxetine (Norepinephrine Reuptake inhibitor, NRI) as adjunct treatments to risperidone and olanzapine for the treatment of negative symptoms of schizophrenia.

Secondary objectives: To assess the efficacy of citalopram and reboxetine as adjunct treatments to risperidone and olanzapine for the treatment of cognitive symptoms of schizophrenia. To compare the efficacy of reboxetine and citalopram as adjunct treatments for the treatment of negative and cognitive symptoms of schizophrenia.

Method: Multicentric, randomized double-blind clinical trial compared to placebo with a six months follow-up. A total of 249 patients with a diagnosis of schizophrenia (DSM-IV criteria) and significant negative symptoms, will be recruited in the 9 participating centres. Variables: sociodemographic and clinical variables (PANSS, SANS, CGI global, GAF,LSP, Hamilton scale, BACS)

Inclusion Criteria:

• Diagnosis of schizophrenia (DSM-IV criteria)
• Stable doses of antipsychotic medication (olanzapine, risperidone)for at least 60 days prior to study initiation
• Presence of significant negative symptoms (defined as one or more negative symptom score grater than 4 in the PANSS scale) (Kay 1987)
• Patients have to give written informed consent to participate in the study

Exclusion Criteria:

• Patients with a substance abuse/dependence diagnosis in the previous six months.
• Mental Retardation.
• Patients taking antidepressant in the last 4 months before the trial.
• Patients taking other antipsychotic medication, except: sinquan 100, Entumine 40, Largactil 100 and Seroquel 200.
• Patients who score more than 20 in Hamilton Rating Scale for Depression.
• Pregnancy or lactation.
• Serious impaired kidney function.
• History of hemorrhagic disorders.
• Reboxetine or citalopram allergy.