To our knowledge, this article presents the first international
data on the prevalence of DSM-IV BP and the
broader BPS using common diagnostic procedures and
methods. In a combined sample of 61 392 adults from
11 countries, the total lifetime prevalences were 0.6% for
BP-I, 0.4% for BP-II, and 1.4% for subthreshold BP, yielding
a total BPS prevalence estimate of 2.4% worldwide.
Comparable 12-month prevalence rates were 0.4% for
BP-I, 0.3% for BP-II, and 0.8% for subthreshold BP, with
a total 12-month BPS prevalence of 1.5%. These rates are
somewhat lower than those from earlier reviews of European
studies4 and international studies,8 which yielded
aggregate estimates of 1.5% and 0.8% for BP-I and BP-II,
respectively, but with a far wider range of estimates than those reported hereIn fact, variation in prevalence rates
in these studies was attributed primarily to differences
in the diagnostic interviews and definitions that were used
to characterize BP.6 The use of common diagnostic definitions
in theWMHreduces the methodologic diversity
that has hindered international prevalence estimates and
prevented accurate descriptions of the personal and economic
impacts of this disorder