The material in this monograph was obtained by the authors in years of research carried out at Kursk State Medical University, Russia. This original, evidence-based research studied the behavior and effects of peptide hormones (melanocortins) and corticosteroids on the excitability and interaction of brain structures. Multiple objective indicators of brain functioning were recorded, taking into account behavioral, motor and visceral manifestations; stereotactic technique, electroencephalography, electrocardiography, electromyography, neuropharmacological and structural-functional analysis were used. The mechanisms of hormonal influence on integrative brain activity that ensure the selection and maintenance of biologically adequate behavior and adaptation have been established. Due to the findings of this research, this book explores the origin of mental disorders in diseases of the pituitary and adrenal glands and during hormonal therapy, and to substantiate the purposeful synthesis of active oligopeptides as new drugs. The book will be of use to physiologists, pathophysiologists, endocrinologists, neuropathologists, psychiatrists, university students, and doctors taking upgrading courses.