[Ultrastructural changes in platelets and their relationship with serotonin metabolism in patients with schizophrenia treated with olanzapine].

An aim of the study was to investigate the effect of olanzapine treatment on platelet ultrastructure and to search for its association with serotonin metabolism in patients with schizophrenia. Platelets of 59 patients with chronic (attack-like schizophrenia) treated with olanzapine and 31 health people were explored. Based on the data on the platelet ultrastructure, authors studied the content of functionally activated vacuolated platelets (VP) and less active granular platelets (GP) as well of platelet serotonin (PS). VP content was higher in patients compared to the control group (+57%, p<0.001). After treatment for 8 and 28 weeks with olanzapine, it decreased and reached the control level (52% and 57%, respectively). There were significant negative correlations between % VP and PS before treatment (r= -0.30, p=0.02) and 8 week after treatment (r= -0.29, p<0.04) and a positive correlation between the decrease in % VP and increase in the PS levels during 8-week treatment (r=0.34, p=0.008). The association between increased platelet vacuolization and decreased PS content in schizophrenia was demonstrated for the first time. This association disappeared after treatment that led to the normalization of % VP and PS levels.