Changes in platelet aggregatory responses to collagen and 5-hydroxytryptamine in depressed, schizophrenic and manic...

The changes in the aggregatory response of platelet rich plasma obtained from a group of depressed, schizophrenic and manic patients fulfilling the DSM-III-R criteria were compared with age and sex matched control subjects. The 5-hydroxytryptamine induced aggregatory responses were significantly decreased in the depressed and schizophrenic patients during the active phase of their illness but returned to normal following clinical recovery. The collagen induced aggregatory responses were decreased in the schizophrenic and manic patients and remained decreased despite clinical recovery. No changes were found in the aggregatory responses to adenosine diphosphate, noradrenaline or adrenaline. The results of this study suggest that changes in the polyunsaturated fatty acid composition of the platelet membrane (collagen effect) and the 5-hydroxytryptamine type 2 receptor (5-HT effect) may occur in these major psychiatric disorders.