Development and validity of two-question screening test for depressive disorders in Northeastern Thai community

Abstract 

Objectives

(1) To develop a screening test for depressive disorders which is simple and short. (2) To determine the diagnostic accuracy of this screening test in Northeastern Thai community.

Methods

From August 2006 through October 2006, two phases of tool development were conducted. The first phase, a two-question screening test of depressive disorders was developed by selecting the dialect words to express depressive mood among Northeastern Thai population. The first item represented depressive mood and the second item represented loss of interest or pleasure in doing things. The second phase, a cross-sectional criterion standard validation study was conducted using stratified cluster randomization to identify 1002 subjects ≥18 years of age in 17 villages in nine districts of Yasothorn province. The two-question screening test was used to identify subgroups of subjects positive of both, positive of either one, and negative of both items. Psychiatrists then determined their diagnoses of mood disorders by administering a structured psychiatric examination (M.I.N.I.) that employed Diagnostic and Statistical Manual of Mental Disorder Text Revision (DSM-IV-TR). Data analysis used STATA 8.0 to calculate the sensitivity, specificity, positive predictive value, negative predictive value, percent of correct classified, and prevalence of depressive disorders with 95% confidence interval.

Results

Of 1002 subjects, female were more predominant (58%), with mean age of 41.5 years. The overall time point rate of depressive disorders was 5.9% (95% CI=4.3–7.1%). Major depressive disorder 3.7% (95% CI=2.5–4.9%) and dysthymia 2.4% (95% CI=1.5–3.3%) occupied the preceding position. The first question of screening test was more positive 3 times than the second one. It showed a high sensitivity of 96.5% (95% CI=95.4–97.6%) but low specificity of 45.6% (95% CI=42.5–48.7%). The second question showed a low sensitivity of 71.9% (95% CI=69.2–74.7%) but high specificity of 84.1% (95% CI=81.9–86.4%). When either one of two questions was positive, this test showed high sensitivity of 96.5% (95% CI=95.4–97.6%) and the positive likelihood ratio was 1.74 (95% CI=1.61–1.88). If both of two questions were positive, it showed high specificity of 85.1% (95% CI=82.9–87.3%) and the positive likelihood ratio was 4.82 (95% CI=3.86–6.02).

Conclusion

Two questions for screening of depression would detect most cases of depressive disorders in the Thai community which has the advantage of brevity, high sensitivity and specificity.

Keywords: Two-question screening test, Depressive disorder, Thai community, Sensitivity, Specificity, Prevalence