The pathophysiology of tardive dyskinesia (TD) is not completely understood.

To assess the relationship of TD with 5-HT2A receptor gene, serotonin transporter gene (5 HTT), and catechol-o-methyltransferase (COMT) gene polymorphisms.

Our study comprised 111 unrelated subjects who strictly met DSM-IV criteria for schizophrenia and 32 TD, and 79 healthy unrelated controls; all the subjects were of Turkish origin. The analyses of 5-HT2A receptor gene, 5 HTT gene, and COMT gene polymorphisms were performed using polymerase chain reaction (PCR) technique.

The polymorphisms of these genes were not significantly different between the schizophrenic patients, TD and control subjects.

Our findings indicated that 5-HT2A receptor gene, 5 HTT gene, and COMT gene polymorphisms were similar in schizophrenia with non-TD, schizophrenia with TD, and healthy controls. These polymorphisms, though, do not help to evaluate the susceptibility to TD.

Schizoaffective disorder is a disease with both affective and psychotic symptoms. In this study, we aimed to compare oxidative metabolism markers of schizoaffective disorder, bipolar disorder and schizophrenic patients. Furthermore, we also aimed to investigate whether schizoaffective disorder could be differentiated from schizophrenia and bipolar disorder in terms of oxidative metabolism.

Total oxidant status (TOS) and total antioxidant status (TAS) were measured in the blood samples that were collected from schizoaffective patients (n = 30), bipolar disorder patients (n = 30) and schizophrenic patients (n = 30). Oxidative stress index (OSI) was calculated by dividing TOS by TAS.

TOS and OSI were found to be higher in patients with schizoaffective disorder compared with those in schizophrenia and bipolar disorder patients. TAS was not significantly different between the groups.

Schizoaffective disorder was found to be different from bipolar disorder and schizophrenia in terms of oxidative parameters. This result may indicate that schizoaffective disorder could differ from bipolar disorder and schizophrenia in terms of biochemical parameters. Increased TOS levels observed in schizoaffective disorder may suggest poor clinical course and may be an indicator of poor prognosis.