CHI3L1 and schizophrenia: That the younger schizophrenic case (age 32) had almost no CHI3L1 positive astrocytes while the other two cases (ages 52 and 56) had more CHI3L1 positive astrocytes raises the question whether there is a relationship between CHI3L1 expression and schizophrenia or it is just age-related reactive gliosis.