Genetic and molecular investigations of bipolar disorder responsive to lithium

Bipolar disorder is a serious mental illness associated with significant morbidity and mortality and high cost to society. It has been long recognized that genes play a role in the causation of bipolar disorder, but no such concrete genes have been found yet. In our previous work funded by the CIHR we studied a large sample of patients with bipolar disorder and their families. The patients also shared the characteristic of being excellent responders to prophylactic lithium treatment. We have chosen this homogeneous group to increase the chances of positive findings and to better understand whether genetic mechanisms influence the treatment outcome as well. In these studies we have identified several chromosomal regions likely to harbor genes for bipolar disorder and/or the treatment response. We now propose four complementary genetic and biochemical studies to identify and characterize genes predisposing for bipolar disorder. Finding such genes will have significant implications for our understanding of the illness, for developing new treatments, and for understanding the role of stress and other factors that can trigger the illness in genetically predisposed individuals.