Blood serum concentrations of kynurenic acid in patients diagnosed with recurrent depressive disorder, depression in bipolar disorder, and schizoaffective disorder treated with electroconvulsive therapy

Aim: The aim of the present study was to compare blood serum kynurenic acid (KYNA) concentrations measured before ECT and after 1, 6 and 12 electroconvulsive treatment (ECT) sessions in patients with diagnoses of recurrent depressive disorder (RDD), depression in bipolar disorder (DBD) and schizoaffective disorder (SAD). Subjects and methods: The study group comprised of 50 patients with ICD-10 diagnoses of RDD, DBD and SAD. Blood serum KYNA concentrations were determined and clinical assessment was performed using the MADRS and the GAF scale. Results: Significant differences were found in blood serum KYNA levels between RDD, DBD and SAD patients treated with electroconvulsive therapy and healthy controls: 1) KYNA concentrations in DBD patients measured before ECT and after 12 ECT sessions were significantly lower than in the control group; 2) KYNA concentrations in the serum of RDD patients measured before ECT and after one and 12 ECT sessions were significantly lower than in the control group, while those measured after 6 ECT session did not differ significantly from KYNA concentrations in healthy controls; 3) higher pre-treatment blood serum concentrations of KYNA in DBD patients correlated with a higher number of illness phases and poorer general functioning before treatment; 4) significant relationships were found between higher blood serum concentrations of KYNA in RDD patients after 1 ECT session and male gender, and between higher KYNA concentrations after 6 ECT sessions and increased depression and poorer functioning before treatment in those patients. Conclusions: Results show that KYNA concentrations in all diagnostic groups were lower before ECT ( not statistically significant for the SAD group) and that there were no significant changes in those concentrations ( compared with the baseline) during ECT.