NEUROBIOLOGY OF PSYCHIATRIC DISORDERS

Abstract

Mental disorders represent a major global health challenge, affecting hundreds of millions of individuals across diverse populations. Despite decades of clinical and scientific research, the precise neurobiological foundations of these conditions remain only partially understood. This chapter provides a broad overview of the neurobiological underpinnings of key psychiatric illnesses, including major depressive disorder (MDD), schizophrenia, anxiety disorders, and autism spectrum disorder (ASD). It highlights central mechanisms such as dysregulation of neurotransmitter systems, disturbances in neuroendocrine pathways, neuroinflammatory processes, and structural or functional abnormalities within neural circuits. In addition, genetic and epigenetic factors are explored as contributors to vulnerability and disease progression. The discussion emphasizes an integrative perspective that bridges fundamental neuroscience with clinical psychiatry, underscoring how biological insights inform diagnosis, treatment, and prevention strategies. By weaving together evidence from molecular biology, neuroimaging, and genetics, the chapter illustrates the complexity of psychiatric disorders and the necessity of cross-disciplinary approaches to advance understanding and improve patient outcomes.