Chapter 2: Neuropsychiatry and Behavioral Neurology

The content traces the historical development of neuropsychiatry and shows how modern neuroimaging techniques, neuropsychological assessment batteries, and clinical neuroscience research have transformed understanding of conditions that blur traditional disciplinary boundaries. The chapter provides comprehensive coverage of major neurological conditions presenting with psychiatric features, including traumatic brain injury with associated mood and personality disturbances, cerebrovascular accidents causing emotional dysregulation and cognitive decline, primary and secondary dementia syndromes with behavioral complications, movement disorders like Parkinson's disease and their neuropsychiatric sequelae, seizure disorders and their psychiatric manifestations, and demyelinating diseases such as multiple sclerosis affecting mood and cognition. A major focus addresses behavioral neurology syndromes, particularly how discrete brain lesions in specific anatomical locations produce characteristic patterns of dysfunction in memory systems, language processing, sustained attention, and executive function domains. The chapter emphasizes the necessity of integrating comprehensive neurological examination, detailed psychiatric interviewing, and formal neurocognitive testing to achieve accurate differential diagnosis and develop effective treatment strategies. Throughout, the material reinforces that understanding the relationship between brain pathology and behavioral presentation is fundamental to contemporary psychiatric practice, requiring clinicians to recognize when psychiatric symptoms reflect underlying neurological disease requiring neurological intervention rather than primary psychiatric disorder necessitating psychopharmacological management.