Stability of the Distribution of Patient Health Questionnaire-9 Scores Against Age in the General Population: Data From the National Health and Nutrition Examination Survey

• Published in: Frontiers in psychiatry Vol. 9; p. 390
• Main Authors: Tomitaka, Shinichiro, Kawasaki, Yohei, Ide, Kazuki, Akutagawa, Maiko, Ono, Yutaka, Furukawa, Toshiaki A
• Format: Journal Article
• Language: English
• Published: Switzerland Frontiers Media S.A 23.08.2018
• Subjects: age; depressive symptoms; exponential distribution; National Health and Nutrition Examination Survey; overlap coefficients; Patient Health Questionnaire-9; Psychiatry; exponential distribution; overlap coefficients; National Health and Nutrition Examination Survey; depressive symptoms; age; Patient Health Questionnaire-9
• ISSN: 1664-0640; 1664-0640
• DOI: 10.3389/fpsyt.2018.00390

Epidemiological studies using the nine-item Patient Health Questionnaire (PHQ-9) have reported inconsistencies regarding the relationship between age and total scores. To determine whether this discrepancy is due to the stability of the distribution of PHQ-9 total scores against age, we investigated whether the total score distribution remains stable during adulthood, and also investigated the mathematical patterns of the total score distribution. The present study utilized data from 15,847 participants of the 2009-2014 United States National Health and Nutrition Examination Survey, all of whom responded to all PHQ-9 items. The stability of the total score distribution among different age groups was examined using overlap coefficients and graphical analysis. High overlap coefficients were observed between all age groups for the distributions of PHQ-9 total scores, suggesting that the distribution of PHQ-9 total scores remains stable against age. Graphical analysis demonstrated that distributions of PHQ-9 total scores were similar across age groups. In addition, distributions of PHQ-9 total scores exhibited an exponential pattern, except at the lower end of the distribution. Our findings indicate that the stability of the distribution of PHQ-9 total scores throughout adulthood may underlie inconsistencies in the evidence regarding age-related changes in total depression scores.