 Blood sample procedure for whole blood serotonin: patients must follow a diet poor in tryptophan during two days before the blood sampling. Blood sample will be performed without premedication between nine and 11 AM. Blood will be withdrawn into tubes containing EDTA acid and aprotinin. Platelet- poor plasma containing up to 0.1 of the original platelet count as assessed by contrast phase microscopy is obtained within 2 hours by centrifugation 2000g, 4C, 15 mn and frozen as 0.5mL aliquots at -80C until assess blind procedures will be used. The whole blood content will by measured by radio-enzymology. 