Brain development and the onset of mood disorders.

Research in mood disorder pathophysiology has stimulated considerable interest in clinical and biologic aspects of mood disorders among children and adolescents. From the clinical perspective, developmental aspects of psychiatric disorders have crystallized in the relatively new theoretical school known as developmental psychopathology. This school attempts to understand the nature of developmental changes in behavior, with the goal of differentiating normal from abnormal stage-related behavior. This perspective has exerted major impact on conceptualizations of psychiatric disorders. From the basic science perspective, biologic findings in emotion have stimulated an integration of basic and clinical approaches to mood disorders. The term emotion is often used to refer to brain states elicited by stimuli for which an organism will extend effort to obtain (rewards) or avoid (punishments). Imaging studies suggest that brain regions engaged by rewarding and punishing stimuli in lower mammals are also implicated in mood disorders. Other studies suggest that environmental factors exert profound effects on the development of these brain regions. The impact of 4 areas of research on our understanding of depression pathophysiology is reviewed: (1) mood disorder onset, (2) structural magnetic resonance imaging (MRI), (3) behavioral or cognitive correlates of major depression, and (4) functional MRI of brain regions engaged across development. This is a US government work. There are no restrictions on its use.