Genetic and environmental factors in bipolar disorder

Abstract

Bipolar disorder (BD) is a highly prevalent mental disease worldwide. This disorder has a genetic inheritance characterized by complex transmission mechanisms involving multiple genes under the influence of several environmental factors. Many investigation strategies have been put forward in order to identify BD susceptibility genes. Twin, linkage and association studies have contributed to the characterization of its herdability through the identification of genomic regions potentially linked to BD and the candidate genes investigation approach. Because of the complexity of the transmission pattern for BD and its phenotypic heterogeneity many difficulties have emerged in defining exact bipolar susceptibility genes. On the other hand, psychosocial studies point out to relevant environmental factors in the etiology of BD. The increasing understanding of gene expression regulation by epigenetic mechanisms, including gene-environment interaction, and the dimensional approach to the mental disorders offer promissing directions to future researches in order to uncover the factors envolved in the etiology of Bipolar disorder.