The Eight-Item Center for Epidemiological Studies Depression Scale in the English Longitudinal Study of Aging: Longitudinal and Gender Invariance, Sum Score Models, and External Associations

The disease burden of depression among older populations is high. Detecting changes in late-life depression is predicated on the seldom-examined assumption of longitudinal measurement invariance (MI). Therefore, we investigated longitudinal MI of the 8-item Center for Epidemiological Studies Depression Scale in core members repeatedly assessed in the English Longitudinal Study of Aging, a nine-wave representative study of the English population above 50 years of age (initial N = 11,391). Based on prior literature, we tested MI of a one-factor solution, a one-factor solution with correlated errors of reversely coded items, and a two-factor solution (depressed affect/somatic complaints). For all factor solutions, residual MI was confirmed across nine waves and gender. Sum score models (i.e., all factor loadings constrained to equity) had a good fit. Depression scores correlated with psychiatric diagnoses, ill health, lower life quality, and female gender. Associations slightly differed depending on the factor solutions, signifying their applicability across contexts.

Automated summary

The disease burden of depression is high among older populations. This study investigated the longitudinal measurement invariance (MI) of the 8-item Center for Epidemiological Studies Depression Scale in the English Longitudinal Study of Aging. The results showed that the scale had good measurement invariance across nine waves and gender, and the depression scores were associated with psychiatric diagnoses, ill health, lower life quality, and female gender. The choice of factor solutions slightly influenced these associations.