Platelet glutamate dehydrogenase activity and efficacy of antipsychotic therapy in patients with schizophrenia

BACKGROUND: Evaluation of possible relationship between platelet glutamate dehydrogenase (GDH) activity and mental state of schizophrenia patients after antipsychotic pharmacotherapy. METHODS: Patients (n = 50) with chronic paranoid schizophrenia (F20.0) initially in acute psychotic state were examined before and after a treatment course with antipsychotics. When assessing the patients' states using PANSS, the "responder" category was attributed to those patients who had not less than 30% reduction in the score for the corresponding PANSS "subscale". The control group (n = 48) was ageand gender-matched with the patient group. Platelet glutamate dehydrogenase (GDH) activity was measured in patients twice, before and after the treatment course, and once in controls. RESULTS: Significantly reduced GDH activity was found in patients compared with controls. The patient group was divided into two subgroups according to median GDH activity at baseline: above and below the median GDH, subgroup 1 and subgroup 2, respectively. GDH activity significantly increased from its level at baseline after antipsychotic treatment in subgroup 2. Distribution of non responders / responders to antipsychotic treatment (by PANSS scores) was significantly uneven among subgroups 1 and 2. In subgroup 1, GDH activity levels significantly correlated with PANSS scores after the treatment course. CONCLUSIONS: Baseline platelet GDH activity might serve as a predictor of antipsychotic therapy efficacy in schizophrenia patients.