Gastrin-releasing peptide (GRP) is a mammalian counterpart of the amphibian peptide bombesin (BB) that stimulates cell proliferation, acts as a growth factor in the pathogenesis of many types of cancer, and regulates several aspects of neuroendocrine function. BB and GRP act by binding to the GRP-preferring type of BB receptor (GRPR, also known as BB2 receptor), a member of the superfamily of G-protein coupled membrane receptors. This review summarizes recent evidence from animal and human studies indicating that abnormalities in GRPR function in the brain might play a role in the pathogenesis of neurological and psychiatric disorders, and suggesting that BB, GRP, and GRPR antagonists might display therapeutic actions in central nervous system diseases. Recent patent applications on GRPR-related methods for treating brain disorders are introduced.