It has been suggested that schizophrenic negative symptoms may be manifestations of regionally deficient CNS dopaminergic activity. We sought to test this hypothesis by openly treating patients on chronic antipsychotic medication who showed prominent negative symptoms with low-dose selegiline.

Eighty patients meeting DSM-IV-TR criteria for chronic schizophrenia with prominent negative symptoms (Positive And Negative Symptoms of Schizophrenia-Negative subtype>15) were studied. Subjects had been kept at their current antipsychotic medication dose levels for at least a month before the study, which was continued unchanged throughout the trial. Over 6 weeks of selegiline treatment, subjects were randomly divided into three subgroups (for one group Selegiline 5 mg/day, for the second 10 mg/day, and for the third placebo was added to the regimen). Patients were assessed through and after 6 weeks by PANSS. Results analyzed with ANOVA and t tests

Eight subjects had significant increase in their positive symptoms and were excluded from the study and 4 patients could not continue the study because of severe side effects. Mean age of patients was 47.62 and mean duration of hospitalization was 8.94 years. Although in both groups who received 5mg/day and 10 mg/day selegiline, in 6 weeks, significant improvement in negative symptoms was seen. But, no significant difference in reduction of negative signs was seen in three subgroups (selegiline 5 mg/day, 10 mg/day, or placebo(P=0.98).

Selegiline was not effective on negative symptoms of schizophrenia for inpatients. This inadequacy was true when seligiline was added to risperidone, or clozapine.