PERIPHERAL SEROTONIN MEASURES IN PREPUBERTAL PSYCHIATRIC-INPATIENTS AND NORMAL-CHILDREN - ASSOCIATIONS WITH SUICIDAL-BEHAVIOR AND ITS RISK-FACTORS

Background: This study reports relationships between suicidal behavior and its risk factors in prepubertal children and whole blood and plat elet serotonin-related measures. Methods: Seventy-five prepubertal psy chiatric inpatients including 23 (30.7%) nonsuicidal, 32 (42.7%) with suicidal ideation, and 20 (26.6%) with a suicide attempt were compared to 35 normal prepubertal controls with regard to platelet serotonin c ontent serotonin-amplified platelet aggregation, and whole blood trypt ophan. Results: Mean whole blood tryptophan content was significantly lower among inpatient children,vith a recent suicide attempt than amon g normal controls or inpatients,vith suicidal ideation (F = 3.94, df = 3.54, p less than or equal to .01). Inpatient children with a mood di sorder had significantly higher platelet serotonin content than inpati ents,without a mood disorder (F = 3.86, df = 2,80, p less than or equa l to .03), Racial/ethnic differences were also observed for inpatients and normal controls, with whites having significantly lon er levels o f platelet serotonin (expressed as ng/mL blood or ng/10(9) platelets) than blacks or Latinos. Blacks had significantly higher levels of whol e blood tryptophan than other racial/ethnic groups. Conclusions: The r esults suggest that whole blood tryptophan and platelet serotonin cont ent should be studied for their predictive validity as risk factors fo r suicidal behavior in youth while controlling for racial/ethnic diffe rences. (C) 1998 Society of Biological Psychiatry.