Treatment response in depressed patients with enhanced Ca mobilization stimulated by serotonin

Serotonin (5-HT)-stimulated intraplatelet calcium (Ca) mobilization has bee n shown to be enhanced in nonmedicated depressive patients by many studies. However, there has not been any longitudinal follow-up study of this param eter. We examined the relationship between treatment response and pretreatm ent valve of tie 5-HT-induced Ca response. The 5-HT(10 muM)-induced intrapl atelet Ca mobilization was measured in 98 nonmedicated depressive patients (24 bipolar disorders, 51 melancholic major depressive disorders, and 23 no n-melancholic major depressive disorders). These patients were followed tip prospectively for a further period of five years. The depressed patients w ith enhanced Ca response to 5-HT in bipolar disorders exhibited a good resp onse to mood stabilizers brit those with major depressive disorders showed, ed a poor response to antidepressants. These findings suggest the possibili ty that the 5-HT-induced intraplatelet Cn response may be a good predictor of treatment response in depressed patients. Longer longitudinal follow-up studies are needed in larger samples to examine if this parameter may De a specific biological marker for unipolar-bipolar dichotomy. (C) 2000 America n College of Neuropsychopharmacology. Published by Elsevier Science Inc.