USA has largest number of people diagnosed as bipolar

From The LA Times:

Bipolar disorder, or manic depressive illness, occurs in 2.4% of people worldwide at some point in their lives, a new study suggests.

Researchers conducted interviews of almost 62,000 people in 11 nations as part of the World Health Organization's World Mental Health Survey Initiative. The point was to measure rates of different types of bipolar disorders.

They spoke to residents of Brazil, Bulgaria, Colombia, India, Japan, Lebanon, Mexico, New Zealand, Romania, Shenzen (China) and the U.S. The United States led with 4.4% of people who had experienced a bipolar spectrum disorder at some point in their lifetime. That number dropped to 2.8% for people who said they had had the disorder within the prior 12 months. But the U.S. still led the pack.

The study also found that those who had bipolar symptoms also had another disorder. "Most striking, 1 in every 4 of 5 persons with BPD [people with bipolar I or II disorder] had made suicide attempts," the study said. Data were collected between 2002 and 2007 in the report published online in the March issue of Archives of General Psychiatry.

There's no doubt the condition is devastating. The study begins: "Bipolar disorder is responsible for the loss of more disability-adjusted life-years than all forms of cancer or major neurologic conditions such as epilepsy and Alzheimer's disease."

The National Institute of Mental Health describes the different types of bipolar disorders measured in the report this way:

"Bipolar I disorder is considered the classic form of the illness, in which a person experiences recurrent episodes of mania and depression. People with bipolar II disorder experience a milder form of mania called hypomania that alternates with depressive episodes. People with BD-NOS, sometimes called subthreshold bipolar disorder, have manic and depressive symptoms as well, but they do not meet strict criteria for any specific type of bipolar disorder noted in the DSM-IV [Diagnostic and Statistical Manual of Mental Disorders]. Yet, BD-NOS can significantly impair those who have it."

And the researchers themselves concluded this as well: "… Treatment needs for BPS [bipolar spectrum disorder] are often unmet, particularly in low-income countries."