CHICAGO: About 4.4 per cent of adults in the United States have experienced a form of bipolar disorder in their lifetime, according to a study published on Monday.

That is more than four times more common than previously thought, the study found. In addition, many of those people are not receiving the treatment they need because they are not being properly diagnosed, it said.

Bipolar disorder is a leading cause of premature death due to suicide, drug abuse and associated health conditions such as diabetes and heart disease.

It causes mood fluctuations between periods of depression and periods of mania, which are characterised by impulsive behaviour.

Bipolar disorder typically first strikes when people are in their late teens and early twenties and the episodes last an average of 10 years, the study found.

“Since the mean age at onset of bipolar disorder occurs at one of the most critical periods of educational, occupational and social developments, its consequences often lead to lifelong disability,” wrote lead author Kathleen Merikangas of the National Institute of Mental Health.

Merikangas and her colleagues interviewed and diagnosed 9,282 people chosen to represent the general population between February 2001 and April 2003 to assess the presence of bipolar disorder and other psychiatric conditions.

They found that nearly all of the patients with bipolar disorder had another psychiatric condition, such as an anxiety disorder or substance use disorder.

While 80 per cent of those with lifetime bipolar disorder received treatment, most had sought treatment for the depression rather than for the manic symptoms. Less than a quarter of bipolar patients received appropriate medication.

“Although most individuals with bipolar disorder receive treatment owing to co-morbid disorders, the lack of recognition of their underlying bipolarity leads to only a few receiving appropriate treatment,” the authors wrote.—AFP