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 platelet serotonin-related measures.

METHODS

Seventy-five prepubertal psychiatric 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 content, serotonin-amplified platelet aggregation, and whole blood tryptophan.

RESULTS

Mean whole blood tryptophan content was significantly lower among inpatient children with a recent suicide attempt than among normal controls or inpatients with suicidal ideation (F = 3.94, df = 3.54, p < or = .01). Inpatient children with a mood disorder had significantly higher platelet serotonin content than inpatients without a mood disorder (F = 3.86, df = 2.80, p < or = .03). Racial/ethnic differences were also observed for inpatients and normal controls, with whites having significantly lower levels of platelet serotonin (expressed as ng/mL blood or ng/10(9) platelets) than blacks or Latinos. Blacks had significantly higher levels of whole blood tryptophan than other racial/ethnic groups.

CONCLUSIONS

The results suggest that whole blood tryptophan and platelet serotonin content should be studied for their predictive validity as risk factors for suicidal behavior in youth while controlling for racial/ethnic differences.