S100B is a 21 kDa protein expressed primarily in astrocytes and has been related with brain dysfunction. There is evidence for increased S100B in schizophrenia, including first-episode psychosis (FEP), and in epilepsy specially after seizures. Pico and nanomolar levels of S100B are neurotrophic and micromolar levels are toxic and apoptotic.

To assess serum levels of S100B at admission and at discharge in a patient with FEP who had comorbid juvenile myoclonic epilepsy (JME).

A 23 year-old male was admitted for injury delusions, suspicion and auditory hallucinations that had started in the last three months. In the last year the patient presented progressive social isolation and stopped attending classes. He was diagnosed JME at age 14 and was treated with 1300 mg valproic acid per day. The last seizure was two years ago. Risperidone was started up to 8 mg per day and valproic acid was continued. He had a progressive clinical improvement and in two weeks was discharged. Serum levels of S100B were determined at admission (3528.23 pg/ml) and discharge (3553.78 pg/ml).

This patient had high levels of serum S100B both at admission and discharge. These levels were ten times higher than previous studies in epilepsy (without psychosis), hundred times higher than previous in psychosis and thousands times higher than in healthy subjects. We interpret these results as an intense activation of astrocytes by a double brain insult. Monitoring this patient during more time will show the evolution of S100B with antipsychotic treatment.