PROS1 and schizophrenia: In this review, we analyze the links between schizophrenia and elements that modulate the coagulation pathway, with particular emphasis on tPA and protein S. First, we describe the physiological roles of tPA and protein S, presenting evidence that the somatic comorbidity and laboratory abnormalities of schizophrenia can be related to decreased activity of tPA and/or protein S (Table 1).