Given recent data that demonstrate peripherally administered NRG1 peptides can cross the blood brain barrier (BBB) of neonatal rodents and exert lifelong behavioral and neurochemical effects [23], [24], and observation that NRG3 is pathologically elevated in the brains of patients with schizophrenia [13], we synthesized the bioactive NRG3 EGF peptide and investigated its ability to penetrate the neonatal murine BBB comparative to NRG1. The gene discussed is NRG3; the disease is schizophrenia.