Bipolar Disorders and Their Clinical Management, Part I: Epidemiology, Etiology, Genetics, and Neurobiology

The concept of bipolar disorders has undergone a substantial evolution over the course of the past two decades. Emerging scientific research no longer supports the notion of bipolar disorder as a discrete neurobiologic entity. Most likely, there are a number of different biotypes with similar phenotypical manifestations. Advancements in genetic research suggest that bipolar disorders have a polygenetic pattern of inheritance, sharing common genetic underpinnings with a number of other psychiatric disorders, including schizophrenia, autistic spectrum disorder, and major depressive disorder. Contemporary etiological theories are discussed in some detail, inclusive of the role of immune disturbances, oxidative stress, and changes in neuroplasticity and neurotransmission, which underpin functional and structural brain changes associated with bipolar disorders. Contemporary epidemiologic research and understanding of disease evolution are discussed from the perspective of its clinical relevance. Our review provides a succinct summary of relevant literature. This review contains 4 figures, 2 tables, and 80 references. Key Words: bipolar disorders, endocrine disturbances, epidemiology, genetics, glia, immunity, neurobiology, neuroplasticity, neurotransmitters