Prevalence of bipolar disorder among residents aged 15 years and older in Hunan province: a cross-sectional study

  Objective  To investigate the prevalence and distribution characteristics of bipolar disorder among the residents aged 15 years and older in Hunan province for promoting mental health among the residents.

  Methods  We conducted a survey on bipolar disorder among permanent residents aged≥15 years recruited with stratified multistage cluster random sampling in 123 counties or districts of Hunan province during February and June 2015. The modified 12-Item General Health Questionnaire (GHQ-12) and clue investigation were used in mental disorder screening and then Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders Fourth Edition, Text Revision DSM-IV-TR Axis I Disorders, Research Version, Patient Edition (SCID-I/P)-Chinese version was adopted in the diagnosis of bipolar disorder among the participants with mental illness. The prevalence, distribution characteristics and influencing factors of bipolar disorder among the participants were analyzed.

  Results  Of the 84 242 residents in the study, 72 999 (86.65%) completed the screening test, of which, 5 869 were interviewed by psychiatrists with SCID-I/P; and finally, 75 participants were identified with bipolar disorder (43 with phase I, 27 phase II, and 5 with other phase of bipolar disorder; 59 78.67% mainly having emotional symptoms and 16 21.33% having psychotic symptoms). Among the 72 999 participants completed the survey, the point and lifetime prevalence rate of bipolar disorder were 1.03‰ ( 95% confidence interval 95% CI: 0.79‰ – 1.26‰) and 1.49‰ (95% CI: 0.75‰ – 2.18‰); there were no significant differences in the point prevalence rate between male and female participants (0.99‰ vs. 1.06‰, χ² = 0.074; P > 0.05) and between urban and rural participants (1.03‰ vs. 1.02‰, χ² ＜ 0.01; P>0.05). The highest time prevalence rate (0.471‰) was observed among the participant aged 45 – 59 years, followed by that (0.421‰) among those aged 60 years and older. Of the bipolar disorder patients diagnosed, 64 (85.33%) had the education of primary school and lower; 33 (44%) were farmers and 20 (26.67%) were not been employed; 29 (38.67%), 23 (30%), and 19 (25.33%) were married, divorced, and unmarried, respectively.

  Conclusion  The study describes the prevalence and characteristics of bipolar disorder among residents of Hunan province and provides essential evidences for developing relevant policies to control the disease.