Cross-sectional and longitudinal relationships between complete blood count measures and adolescent suicidal behavior

Abstract

ObjectiveReplicable biological predictors are needed to distinguish adolescents at risk for suicide attempts (SA) compared to those at risk for suicidal ideation (SI). Early evidence in adults identifies that complete blood count (CBC) measures may be directly related to suicidal behavior (SB). MethodsIn this retrospective chart review, we assessed if CBC measures differed between adolescents psychiatrically hospitalized for SA versus SI, initially in an exploratory test cohort (n = 110, age = 11–18, 67 % female, 72.7 % White) and then in an independent confirmatory replication cohort (n = 97). In longitudinal analyses, we identified if CBC measures predicted future SB over 90 days. CBC measures were also compared to a healthy adolescent cohort (n = 597) and a medically-hospitalized nonsuicidal adolescent cohort (“MH” cohort; n = 51). ResultsSuicide attempters had lower eosinophil percentages, eosinophil counts, and platelet counts as compared to suicide ideators, though in the replication cohort, only eosinophil percentages were lower in suicide attempters. In longitudinal analysis, both lower eosinophil blood counts and percentages were associated with future suicidal behavior. In cross-sectional comparative analyses, the MH cohort had similar or lower eosinophil percentages/counts to adolescents psychiatrically hospitalized with SA. ConclusionsThough lower eosinophil percentages and counts were present in adolescents with recent SA (compared to SI), such effects may be related to physical sequalae of SA. Nevertheless, both lower eosinophil counts and percentages appear to be valuable predictors of prospective suicidal behavior over 90 days amongst psychiatrically hospitalized adolescents. These findings may guide research seeking to effectively identify adolescents at elevated risk of future suicide attempts.