Increased platelet aggregability in major depression?

There is compelling evidence that depression constitutes an independent ris k factor for cardiovascular morbidity and mortality. As exaggerated platele t reactivity is associated with an increased risk of intra-arterial thrombu s formation, we studied platelet aggregability in patients with major depre ssion both before and after 5 weeks of anti-depressant therapy as well as i n healthy control subjects. Twenty-two depressed patients and 24 healthy co ntrol subjects participated in the study. Washed and rediluted platelets we re stimulated with the agonists collagen and thrombin in three concentratio n steps. Depression was associated with a higher aggregability after stimul ation with thrombin in the intermediate concentration and with collagen at the low concentration, with ceiling effects for the other concentrations. A fter 5 weeks of anti-depressant therapy, aggregability was somewhat less ex aggerated, although this effect did not reach statistical significance. We thus conclude that major depression is associated with increased platelet a ggregability, which seems to persist even under a marked improvement in dep ressive symptomatology. This effect may contribute to the increased cardiov ascular morbidity in depressed patients. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.