Serum S100B: A Potential Biomarker for Suicidality in Adolescents?

BACKGROUND Studies have shown that patients suffering from depression or schizophrenia often have immunological alterations that can be detected in the blood. Others reported a possible link between inflammation, a microgliosis and the blood-brain barrier (BBB) in suicidal patients. Serum S100B is a marker of BBB function commonly used to study cerebrovascular wall function. METHODS We measured levels of S100B in serum of 40 adolescents with acute psychosis, 24 adolescents with mood disorders and 20 healthy controls. Patients were diagnosed according to DSM-IV TR criteria. We evaluated suicidal ideation using the suicidality subscale of the Brief Psychiatric Rating Scale for Children (BPRS-C). RESULTS Serum S100B levels were significantly higher (p<0.05) and correlated to severity of suicidal ideation in patients with psychosis or mood disorders, independent of psychiatric diagnosis. Patients with a BPRS-C suicidality subscores of 1-4 (low suicidality) had mean serum S100B values +/- SEM of 0.152+/-0.020 ng/mL (n = 34) compared to those with BPRS-C suicidality subscores of 5-7 (high suicidality) with a mean of 0.354+/-0.044 ng/mL (n = 30). This difference was statistically significant (p<0.05). CONCLUSION Our data support the use of S100B as an adjunctive biomarker to assess suicidal risk in patients with mood disorders or schizophrenia.