Thrombocytic serotonin concentration in depressed children and adolescents

Abstract

This study pursued the question to what extent a correlation exists between the platelet serotonin concentration and depressive and/or suicidal behaviour in children and adolescents. Within a 16-month period, the platelet serotonin concentration was determined in all admitted inpatients (n = 145, age: 4 to 19 years) by means of fluorescent spectroscopy according to a standardised protocol. The severity of depressive symptoms was assessed by administration of the DIKJ to a subset of patients. The different diagnostic groups were formed according to the criteria of the ICD-10. A decrease in the platelet serotonin concentration was found with increasing age. While platelet serotonin concentrations were higher in male patients than in females, the girls showed higher depression scores on the DIKJ. A negative correlation existed between the platelet serotonin concentration and the degree of depression measured on the DIKJ in all diagnostic groups. Independent of the clinical diagnosis significantly lower concentrations of platelet serotonin were found in children and adolescents who had attempted suicide immediately before admission to hospital. The same is true for the group of depressive disorders, with a subgroup of patients who had attempted suicide shortly before also showing significantly lower concentrations of platelet serotonin. The present investigation supports the contention that depression in childhood and adolescence is related to a lack of serotonin in platelets, respectively, analogous to the platelet model, to a lack of serotonin in central structures, and that a relative serotonin deficiency could thus be an indicator of suicidal ideation.