A community survey of the twelve-month prevalence and correlates of bipolar spectrum disorder in Hong Kong.

Background: Recent community and clinical epidemiological studies have indicated that bipolar spectrum disorder (BSD) is a common illness. No community-based epidemiological study of BSD has been conducted in Chinese and other Asian populations.

Method: A random sample of 3016 Chinese adults underwent a telephone-based community survey that examined their twelve-month prevalences of BSD, sociodemographic characteristics, level of distress, and role impairment using the Sheehan Disability Scale. Bipolar I disorder (BP-I) and bipolar II disorder (BP-II) were based on DSM-IV criteria. Soft bipolar II disorder (Soft BP-II) fulfilled the DSM-IV criteria of major depressive episode and hypomanic episode except that the hypomanic/manic symptoms lasted two to three days.

Results: The lifetime prevalences of manic episode, hypomanic episode, and soft hypomanic episode were 2.2%, 2.2%, and 10.7% respectively. The twelve-month prevalences of BP-I, BP-II, and Soft BP-II were 1.4%, 0.5%, and 1.8%, respectively. Respondents with BSD were more likely to be female, younger, and single than those without. Impairment and distress associated with depressive symptoms were similar across the three groups of bipolar disorders, but those associated with manic/hypomanic symptoms were more severe among respondents with BP-I than BP-II and Soft BP-II. The number of manic/hypomanic symptoms and depressive symptoms did not differ across the three bipolar groups.

Limitation: Structured interview questions based on core DSM-IV mood symptoms might under-estimate hypomania. Detailed sociodemographic information was not available.

Conclusion: BSD was common among Chinese people in Hong Kong and exhibited an epidemiological profile comparable to that of western societies.