Prevalence studies of bipolar disorder are typically carried out by lay interviewers who follow fully structured/fixed interview schemes; responses to single items from such interviews may have limited validity. In addition, diagnoses (and therefore estimates of prevalence) vary depending on whether a categorical or spectrum approach is used. This consideration has led to concerns about the potential for both underdiagnosis and overdiagnosis.The incidence of bipolar disorder is similar in men and women as well as across different cultures and ethnic groups. A 2000 study by the World Health Organization found that prevalence and incidence of bipolar disorder are very similar across the world. Age-standardized prevalence per 100,000 ranged from 421.0 in South Asia to 481.7 in Africa and Europe for men and from 450.3 in Africa and Europe to 491.6 in Oceania for women. However, severity may differ widely across the globe. Disability-adjusted life year rates, for example, appear to be higher in developing countries, where medical coverage may be poorer and medication less available. Within the United States, Asian Americans have significantly lower rates than their African American and European American counterparts. In 2017, the Global Burden of Disease Study estimated there were 4.5 million new cases and a total of 45.5 million cases globally. History
In the early 1800s, French psychiatrist Jean-Étienne Dominique Esquirols lypemania, one of his affective monomanias, was the first elaboration on what was to become modern depression. The basis of the current conceptualization of bipolar illness can be traced back to the 1850s.
Clinical features also differ between those with late-onset bipolar disorder and those who developed it early in life; the former group present with milder manic episodes, more prominent cognitive changes and have a background of worse psychosocial functioning, while the latter present more commonly with mixed affective episodes, and have a stronger family history of illness. Older people with bipolar disorder experience cognitive changes, particularly in executive functions such as abstract thinking and switching cognitive sets, as well as concentrating for long periods and decision-making. Prevention
Attempts at prevention of bipolar disorder have focused on stress (such as childhood adversity or highly conflictual families) which, although not a diagnostically specific causal agent for bipolar, does place genetically and biologically vulnerable individuals at risk for a more severe course of illness. Longitudinal studies have indicated that full-blown manic stages are often preceded by a variety of prodromal clinical features, providing support for the occurrence of an at-risk state of the disorder when an early intervention might prevent its further development and/or improve its outcome. Management
The aim of management is to treat acute episodes safely with medication and work with the patient in long-term maintenance to prevent further episodes and optimise function using a combination of  pharmacological and psychotherapeutic techniques. Hospitalization may be required especially with the manic episodes present in bipolar I. This can be voluntary or (local legislation permitting) involuntary. Long-term inpatient stays are now less common due to deinstitutionalization, although these can still occur.