The early stages of bipolar disorder and recent developments in the understanding of its neurobiology

Abstract

Bipolar disorder is a severe recurrent psychiatric illness that often manifests in adolescence, a time of marked neurobiological change. The current model is one of multiple susceptibility genes interacting with other risk factors leading to alterations in the normal maturational trajectory of the CNS. Longitudinal studies of children of affected parents has enabled mapping of the early natural history of bipolar disorder. Convergent evidence from longitudinal high-risk studies suggest that bipolar disorder evolves in a series of clinical stages from nonspecific childhood disorders to depressive disorders in early adolescence and bipolar spectrum disorders in later adolescence and adulthood. At present, genetic studies and research into specific biological markers in bipolar patients and their family members are underway. Advances in understanding the neurobiological underpinnings of bipolar disorder will require addressing etiological heterogeneity of bipolar disorder and refining the phenotypic definition. In the latter case, the staging model may be a helpful organizing framework.