Genetic linkage studies in bipolar disorder: a review.

For the past 20 years, researchers have been using genetic linkage studies as a tool to better understand the etiology of bipolar disorder. During this time, there have been reports of linkage between the symptom complex of bipolar disorder and 7 genetic markers located on 4 different chromosomal areas. All of these reports continue to be surrounded by controversy causing some observers to consider the field to be ambiguous and contradictory. This review provides some historical perspective on the controversies, while outlining the current status and future direction of the field.