Prevalence of depressive disorders and associated demographic characteristics in Shandong: An epidemiological investigation

Background: Depression is characterized by debilitating symptoms and high recurrence rates, and there are relatively few large-scale epidemiological surveys of depressive disorders conducted in Shandong since 2005. Data from the largest Epidemiological Survey of Mental Disorders conducted in 2015 in Shandong were collected to investigate the prevalence of depressive disorders and associated demographic characteristics in general adult population. Methods: A multi-stage stratified cluster sampling method was adopted to select residents and a two-stage screening and assessment process was used to define the prevalence and characteristics of depressive disorders. Respondents were initially screened using the General Health Questionnaire followed by a structured clinical interview using the DSM-IV criteria. Results: Among 27,489 respondents who completed the survey, 1277 respondents met the diagnostic criteria for depressive disorders. The adjusted prevalence in the last month was 4.86%, among which the prevalence of major depressive disorder, dysthymia, and unspecified depressive disorder were 2.32%, 1.78%, and 0.75%, respectively. 40.35% of depression patients had moderate or severe functional impairment and only 10.65% of patients had visited a psychiatric service. Univariate and multivariate analyses revealed that age, gender, occupation, education, marital status, and urban/rural living were associated with the prevalence. Limitations: The key limitation is that this is a cross-sectional survey therefore cannot draw any causal relationship between risk factors and disease progression. Conclusions: Findings from this largest epidemiological study reveal current prevalence of depressive disorders and associated demographic factors and offers opportunities for policy makers and health-care professionals to improve mental health provision in Shandong.