Bipolar depression is a more serious and impairing mood disorder than unipolar depression. Yet, it is under-recognized and has not been systematically studied in Hong Kong before. The Hong Kong Mood Disorders Center of the Faculty of Medicine, commissioned the Hong Kong Institute of Asia -Pacific Studies to conduct a large -scale telephone survey of this illness from 16 January to 16 February 2007.
The survey randomly selected and interviewed 3,016 adults aged 18-65. According to the diagnostic criteria of the American Psychiatric Association and other internationally established research centers, bipolar depression is defined as the presence of five or more physical and/or psychological symptoms of major depression that must include persistent low mood or energy level, accompanied by obvious functional impairment for two weeks or more. In addition, there are at least four concurrent hypomanic symptoms manifesting as excessively high energy levels or irritability for at least two consecutive days.
The findings show that the one-year prevalence of depression is 8.8% while the one-year prevalence of bipolar depression is 3.9%. This indicates that one out of eight Hong Kong adults may suffer from major depression, and of these eight individuals, three suffer from bipolar depression. Accordingly, it is estimated that about 180,000 adults suffered from bipolar depression in the previous one year. Regarding risk factors, females (4.9%) have a 1.89 times higher rate of bipolar depression than males (2.7%). Young age, unemployment and divorce also increase the risk of bipolar depression. Compared to individuals with unipolar depression, those with bipolar depression are more likely to abuse alcohol and drugs, and to be suicid al. Specifically, 56.9% of adults with bipolar depression thought about suicide , 25% had suicidal plans , and 9.5% made actual suicide attempts in the previous one year. Yet, less than one-fifth of individuals suffering from either unipolar or bipolar depression have sought help from mental health professionals.
The present survey confirms studies conducted worldwide that bipolar depression is a common, serious, and under-treated mood disorder. This calls for efforts to encourage early recognition and treatment of bipolar depression in Hong Kong.
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