Age-Related Changes in Item Responses to the Patient Health Questionnaire-9: Evidence From the National Health and Nutrition Examination Survey

Abstract

Background Epidemiological studies have shown that total scores in depression screening scales change with age, but the mechanism underlying these age-related changes remains unclear. Previous research has indicated that item responses in depression screening scales exhibit characteristic distributions in the general population. We analyzed Patient Health Questionnaire-9 (PHQ-9) data from a representative survey conducted in the USA, to determine how the response pattern for each item changed with age and whether the pattern of responses contributed to age-related changes in total scores. Methods We analyzed PHQ-9 data for 17,274 participants in the 2011–2016 National Health and Nutrition Examination Survey. The PHQ-9 allows respondents to self-rate the frequency of depressive symptoms using a four-point scale ranging from “not at all” to “nearly every day”. Results The lines for all nine item responses followed the same characteristic pattern across all age groups, which was marked by intersection at a single point between “not at all” and “several days” and parallel patterns between “several days” and “nearly every day” on a logarithmic scale. The probability of “nearly every day” showed a reverse U-shaped pattern, in that it was low from 12–29 years, increased during 30–50 years, and then decreased at ≥60 years. The age-related change in the probability of a response of “nearly every day” coincided with the trajectory of the PHQ-9 total scores. Conclusions This study demonstrated that item responses for the PHQ-9 followed a similar mathematical pattern across the adult lifespan. Moreover, our findings suggested that the probability of a response of “nearly every day” played an important role in age-related changes in PHQ-9 total scores across adulthood.

The GAD-7 and the PHQ-8 exhibit the same mathematical pattern of item responses in the general population: analysis of data from the National Health Interview Survey

“…For both sexes, the item responses for the GAD-7 and PHQ-8 exhibited the same mathematical pattern. Previous analyses have reported that the item responses for depression rating scales show the same mathematical pattern regardless of age and nationality [13,32]. Taken together, item responses on the GAD-7 and depression rating scales may follow the same characteristic pattern regardless of demographic factors, such as sex, age, and nationality.…”

Exploring Social Determinants of Posttraumatic Pain, Distress, Depression, and Recovery Through Cross-Sectional, Longitudinal, and Nonlinear Trends

“…Prior research in this area appears inconsistent. Wada et al40 found a similar negative association between age and PHQ-9 score in a sample of 356 patients undergoing cancer treatment, while Tomitaka et al41 found that PHQ-9 score increased to middle age, then decreased from age 60 and over in a sample of 17,000 US adults. It appears that further work is warranted, and we note that our results align with those of Tomitaka with support for a potential nonlinear association between these variables, though we again highlight that neither linear nor quadratic functions were statistically significant.…”