Modifications of biochemical parameters in blood platelets of schizophrenic and depressive patients

The blood platelet may be considered as an interesting model of the serotoninergic neuron in biology and pharmacology. We studied some platelet parameters in neuropsychiatric patients (depressive and schizophrenic ones): serotonin (5-HT) uptake was abnormal for all schizophrenics and lowered for depressive patients; uptake of mepacrine, a marker of 5-HT passive diffusion, was diminished for manic patients; MAO and glutathione peroxidase activities were modified, essentially for paranoid schizophrenics and some alterations of the platelet hydroxyindole level were noticed; during treatment with neuroleptics of antidepressants biological parameters led to 'normality'. These results are discussed with clinical data and a hypothesis is proposed to join the biological modifications of paranoid schizophrenics.