What Do EURO-D Scores Capture? Disentangling Trait and State Variances in Depression Symptoms Across the Adult Life Span in Nine European Nations.

The primary purposes of the present study were to determine (a) whether the EURO-D measures trait (i.e., time-invariant) versus state (i.e., time-variant) aspects of depression and (b) whether these aspects are stable across countries and ages. In five waves of the SHARE survey (a nationally representative Survey of Health, Ageing, and Retirement in Europe), we estimated trait-state-occasion models (TSO), including multiple-nation TSO, based on data from nine European nations over a 10-year period. Also, we used local structural equation modeling to test for the moderating effects of age on the TSO parameters. Our main findings were: (a) there were differences in the trait/state variances of depressive symptoms across nations. The amount of trait variance was above 60% for Belgium, Denmark, and France. It was between 50% and 60% for Austria, Germany, Sweden, and Switzerland, while it was below 50% for Italy and Spain. (b) The effects of trait and state were almost equally the source of variance for depression symptoms across ages, with a slight advantage for the effects of trait (56% of the variance). This trend showed substantial stability across the adult life course (from age 40 up to age 95).

The Geriatric Depression Scale: does it measure depressive mood, depressive affect, or both?

OBJECTIVE: Self-report measures of depression are highly important tools used in research and in various healthcare settings for the diagnosis of different levels of depression. The Geriatric Depression Scale (GDS) is the first and the most popular scale used to screen for late-life depression. It is endorsed by the Royal College of Physicians and the British Geriatric Society (1992). The purpose of the present research was to investigate whether scores on the GDS15 capture depressive mood (i.e. trait depression), depressive affect (i.e. short-term depressive state), or both. METHODS: For this purpose, a trait-state model (stable trait, autoregressive trait, and state model) was applied to GDS15 scores obtained at four time points over a 6-year period among a sample of community-dwelling older persons (N = 753). This model allows decomposing the GDS15 scores into three different variance components: stable trait variance, autoregressive trait variance, and state variance. RESULTS: Our findings revealed a general pattern of a major proportion of stable trait (69%) and autoregressive trait (22%) variance and a very smaller amount of state variance (9%) in the GDS scores across 6 years. Age and gender (i.e. being female) were shown to be positively linked to more stable trait variance. CONCLUSIONS: Depression, as assessed with the GDS15 , should be regarded as a relatively stable and enduring trait construct, reflecting a stable core of a person's depressivity. The negligible amount of state elements in the variation of the GDS15 scores provides evidence that changing the context will not be enough to cause significant changes in depressive symptoms. Copyright © 2016 John Wiley & Sons, Ltd.