Results of an international study of the prevalence of bipolar disorder partially funded by NIMH are reported by NIH. The study surveyed bipolar spectrum disorders (bipolar I, bipolar II, and bipolar not otherwise specified) in 11 countries in North America, Europe, Asia, and New Zealand. The overall rate of bipolar spectrum disorder was 2.7 percent of the general population, with 4.4 percent in the United States. Most patients had onset of their bipolar disorder during adolescence, and 75 percent of patients had at least one other co-occurring psychiatric disorder, the most common being anxiety disorders. To read this article in its entirety, click here.