Characteristic distribution of the total and individual item scores on the Kessler Screening Scale for Psychological Distress (K6) in US adults

Shinichiro Tomitaka,Kazuki Ide,Toshiaki A Furukawa,Yohei Kawasaki,Hiroshi Yamada,Yutaka Ono,Maiko Akutagawa

doi:10.1186/s12888-017-1449-1

Shinichiro Tomitaka, Kazuki Ide + Show 5 more

Open Access

https://doi.org/10.1186/s12888-017-1449-1

Copy DOI

Abstract

BackgroundThe distributional pattern of total scores on depression screening scales in the general population has not been well studied. Recent studies suggest that the total scores on depression screening scales follow an exponential pattern, with the exception of the lower end of the distribution. To further investigate the findings, we determined the distributions of the total and individual item scores on the Kessler Screening Scale for Psychological Distress (K6).MethodsData were obtained from the National Survey of Midlife Development in the United States. Participants comprised 6,223 individuals between the ages of 25 and 74. The distributions of the total and individual item scores in various combinations were investigated with histograms and regression analysis.ResultsIrrespective of the combination of items, the total and individual item scores followed an exponential pattern except at the lower scores. The estimated rate parameters of regression analysis were similar among distributions with the same number of chosen items. At the lower scores, the distributional patterns of total scores varied according to the ratio of “a little” to “none” for each item response.ConclusionsThe present results have the potential to estimate the distribution of depressive symptoms in the general population. While the degree of depressive symptoms varies from individual to individual, an entire population may show a certain mathematical distribution.

Highlights

The distributional pattern of total scores on depression screening scales in the general population has not been well studied
Because the degree of depressive symptoms is fundamental to a diagnosis of clinical depression, the severity distribution of depressive symptoms in the general population is a major area of interest within the field of psychiatry [3, 4]
Analyzing almost 25,000 respondents to the Japanese Active Survey of Health and Welfare, we have reported that the distribution of total scores on the Center for Epidemiologic Studies Depression Scale (CES-D) approximates an exponential pattern, with the exception of the lower end of the distribution [11]

Summary

Introduction

The distributional pattern of total scores on depression screening scales in the general population has not been well studied. Population studies of depressive symptoms have been conducted using parametric statistics, factor analysis, and item response theory. These methods are called confirmatory data analysis (CDA), which presupposes a statistical model, tests a hypothesis, and estimates parameters [6]. Exploratory data analysis (EDA) is an inductive approach designed to reveal characteristics and patterns in the data, often with visual methods [6, 7].

Objectives

Methods

Results

Conclusion