Original Research ARTICLE
Item Response Patterns on the Patient Health Questionnaire-8 (PHQ-8) in a Nationally Representative Sample of US Adults
- 1Department of Mental Health, Panasonic Health Center, Japan
- 2Department of Health Promotion and Human Behavior, Kyoto University Graduate School of Medicine/School of Public Health, Kyoto University, Japan
- 3Department of Drug Evaluation and Informatics, School of Pharmaceutical Sciences, University of Shizuoka, Japan
- 4Department of Pharmacoepidemiology, Graduate School of Medicine and Public Health, Kyoto University, Japan
- 5Center for the Promotion of Interdisciplinary Education and Research, Kyoto University, Japan
- 6Center for the Development of Cognitive Behavior Therapy Training, Japan
Recent studies have shown that item responses on the Center for Epidemiologic Studies Depression Scale (CES-D) and Kessler Screening Scale for Psychological Distress (K6) exhibit the same characteristic item response patterns among the general population. However, the distributional patterns of responses on the Patient Health Questionnaire-8 (PHQ-8) among the general population have not been adequately studied. Thus, we conducted a pattern analysis of PHQ-8 item responses among US adults. Data (18,446 individuals) were obtained from the 2015 Behavioral Risk Factor Surveillance Survey (BRFSS). Item responses on the BRFSS version of the PHQ-8 were scored using the number of days response set and then converted to the original 4-point scale. The patterns of item responses were analyzed through graphical analysis. Lines of item responses scored using the number of days response set showed the same pattern among the eight items, characterized by crossing at a single point between “0 days” and “1 day,” and parallel fluctuation from “1 day” to “14 days” on a semi-logarithmic scale. Lines of item responses converted to the 4-point scale also showed the same characteristic pattern among the eight items. The present results demonstrate that the item responses on the PHQ-8 show the same characteristic patterns among items, consistent with the CES-D and the K6.
Keywords: Exploratory data analysis, depressive symptoms, PHQ-8, Item response, Behavioral Risk Factor Surveillance Survey, Exponential distribution, End-digit preference bias
Received: 13 Aug 2017;
Accepted: 09 Nov 2017.
Edited by:Renerio Fraguas, University of São Paulo, Brazil
Reviewed by:Gianluca Serafini, Department of Neuroscience, San Martino Hospital, University of Genoa, Italy
Nefize Yalin, King's College London, United Kingdom
Copyright: © 2017 Tomitaka, Kawasaki, Ide, Akutagawa, Yamada, Ono and Furukawa. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Dr. Shinichiro Tomitaka, Panasonic Health Center, Department of Mental Health, Tokyo, Japan, firstname.lastname@example.org