BDNF and schizophrenia: In a more extensive study conducted by Chen et al [3], serum BDNF levels of 88 patients with schizophrenia who had received no antipsychotic treatments and a control group (n = 90) were compared in an effort to discover the relation between BDNF and schizophrenia subtypes; serum BDNF levels of patients with schizophrenia were significantly lower than those of the control group.