Is Geriatric Depression Scale-15 a suitable instrument for measuring depression in Brazil? Results of a Rasch analysis

Abstract

Depressive symptoms are the most prevalent mental health condition in older adults. Since it cannot be measured directly, the use of instruments is mandatory. The 15-item Geriatric Depression Scale (GDS) is one of the most widely used scales to measure depression in the elderly. It is recognized that the cultural context is a major determinant of the instrument's psychometric performance. Up to the present, this scale has mainly been investigated through classical psychometric approaches. The present study aims to explore whether the 15-item GDS is a suitable instrument in a Brazilian sample. In addition, it explores the potential improvement in the psychometric performance by item refinement. Four hundred twenty-four elderly adults selected through convenience sampling completed the 15-item GDS. Data were analyzed by the Rasch Measurement Model. The Rasch analysis is a powerful modern approach to explore psychometric performance of instruments in health sciences. It examines both the scale and the individual item performance in depth. The 15-item GDS proved not to be suitable in a Brazilian sample. Item misfit and differential item functioning were responsible for considerable misperformance. Scale reduction led to a 10-item structure. This refined format presented adequate psychometric performance and no differential item functioning. The present study offers an alternative and more adequate version of the GDS to be applied in Brazilian subjects. It is also in line with the need for shorter, valid scales in clinical settings. Further investigations are needed to develop a set of cultural-invariant items, which could then be applied in transcultural investigations free of bias.

Evaluating hierarchical items of the geriatric depression scale through factor analysis and item response theory

“…Compared with related studies using the same method of Rasch analysis, there seems to be more item agreement than when using the Classic test theory in other related studies. Our present findings had 67.7% item agreement as with other Rasch analysis conducted by Chachamovich et al. (2010) ​and 83.3% of item agreement with Tang et al.…”

“…Investigations to shorten GDS using IRT are limited (Chachamovich et al., 2010), despite the fact that IRT or Rasch provides some advantage over CTT because IRT has two main models, nonparametric and parametric. Roughly speaking, both have the same principle, focusing on the relation between individual item responses and individual latent trait values, represented by an item response function (Sijtsma and Molenaar, 2002).…”

Tailored Screening for Late-Life Depression: A Short Version of the Teate Depression Inventory (TDI-E)

“…Among the scales designed with the specific aim of screening depression in the elderly, the 30-item GDS was the gold standard (Yesavage et al, 1982). However, it has been repeatedly criticized (e.g., Friedman et al, 2005), mainly because of its length (Jongenelis et al, 2005; Chachamovich et al, 2010). The 15-item GDS-SF, extracted by the full-length form based on the base of diagnostic accuracy criteria (Yesavage and Sheikh, 1986), was also criticized (Chiang et al, 2009; Mitchell et al, 2010a,b; Wongpakaran et al, 2019) because of its lacking unidimensional nature.…”

Comparison of the Geriatric Depression Scale‐15 and the Patient Health Questionnaire‐9 for screening depression in older adults

“…The findings were consistent with the results of the GDS-15 evaluated in Japanese and Brazilian older adults. 10,11 Item 2 in the GDS-15 is "Have you given up your previous hobbies and interests?" and item 9 is "Do you prefer to stay at home rather than do something you are not familiar with?"…”