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).

Conclusions: Our data support the use of S100B as an adjunctive biomarker to assess suicidal risk in patients with mood disorders or schizophrenia.