Toward an Understanding of Bipolar Disorder and Its Origin

Bipolar disorder, a disease with significant morbidity and mortality, continues to present diagnosticand clinical challenges. Lifetime prevalence of bipolar I disorder has been estimated at 1.3%, withan equal distribution between males and females. Recognition of the illness may take years, but mostpatients are diagnosed before the age of 30. The role of genetic influences in bipolar disease is supportedby family studies and high concordance rates among monozygotic twins. Current speculationproposes a likely interaction between genetic predisposition and environmental influences, includingstressful life events. Diagnostic work-up should exclude mania secondary to drug use or general medicalcauses, particularly in patients whose symptoms begin after age 30 and in those with no familyhistory of bipolar or unipolar disease. Patients with cyclothymia or thyroid dysfunction or postpartumwomen are at particular risk for bipolar disease. Substance abuse, which is extremely common amongpatients with bipolar disorder, interferes with diagnosis and can worsen the course of the disease.Alcohol dependence has been reported in approximately one third of those with bipolar I and one fifthof those with bipolar II disorder. To facilitate early diagnosis and effective management, cliniciansshould be aware of the risk factors, possible causes, and comorbidities of bipolar disease.