For the journal, see Neuropsychiatry (journal) Neuropsychiatry is a branch of medicine that deals with mental disorders attributable to diseases of the nervous system. It preceded the current disciplines of psychiatry and neurology, which had common training. However, psychiatry and neurology subsequently split apart and are typically practiced separately. Nevertheless, neuropsychiatry has become a growing subspecialty of psychiatry and it is also closely related to the fields of neuropsychology and behavioral neurology, which is a subspecialty of neurology that addresses clinical problems of cognition and/or behavior caused by brain injury or brain disease of different etiologies.