Optimising the diagnostic performance of the Geriatric Depression Scale María Izal a, ⁎, Ignacio Montorio a , Roberto Nuevo b,c , Gema Pérez-Rojo a , Isabel Cabrera a a Universidad Autónoma de Madrid (Spain), Facultad de Psicología, Spain b Department of Psychiatry, Autónoma University of Madrid, La Princesa University Hospital, Madrid, Spain c Instituto de Salud Carlos III, Centro de Investigación en Red de Salud Mental, CIBERSAM, Spain abstract article info Article history: Received 1 July 2008 Received in revised form 10 December 2008 Accepted 22 February 2009 Keywords: Screening Diagnostic efficiency GDS Older adults The aim of this work is to empirically generate a shortened version of the Geriatric Depression Scale (GDS), with the intention of maximising the diagnostic performance in the detection of depression compared with previously GDS validated versions, while optimizing the size of the instrument. A total of 233 individuals (128 from a Day Hospital, 105 randomly selected from the community) aged 60 or over completed the GDS and other measures. The 30 GDS items were entered in the Day Hospital sample as independent variables in a stepwise logistic regression analysis predicting diagnosis of Major Depression. A final solution of 10 items was retained, which correctly classified 97.4% of cases. The diagnostic performance of these 10 GDS items was analysed in the random sample with a receiver operating characteristic (ROC) curve. Sensitivity (100%), specificity (97.2%), positive (81.8%) and negative (100%) predictive power, and the area under the curve (0.994) were comparable with values for GDS-30 and higher compared with GDS-15, GDS-10 and GDS-5. In addition, the new scale proposed had excellent fit when testing its unidimensionality with CFA for categorical outcomes (e.g., CFI=0.99). The 10-item version of the GDS proposed here, the GDS-R, seems to retain the diagnostic performance for detecting depression in older adults of the GDS-30 items, while increasing the sensitivity and predictive values relative to other shortened versions. © 2009 Elsevier Ireland Ltd. All rights reserved. 1. Introduction The Geriatric Depression Scale (GDS; Brink et al., 1982) is one of the most frequently used instruments in the diagnosis and study of depression in older adults (Mui, 1996; Stiles and McGarrahan, 1998; Jongenelis et al., 2005). The original GDS is a measurement made up of 30 items ('yes'/'no') that was designed to assess the severity of depression in older adults in response to the recognition that depression scales based on the general population might not be adequate for use in the elderly population. In fact, items referred to somatic symptoms were removed from the initial pool in the construction process of the scale (Brink et al.,1982; Yesavage et al.,1983). The GDS has demonstrated high diagnostic precision in identifying depression, although large number of items make its application difficult in a number of health contexts, such as primary health care (Heisel et al., 2005). Moreover, its application to elderly people entails the risk of biases due to fatigue or concentration problems/attention span difficulties (Herrmann et al., 1996), which also increases the time needed to complete it. Depression often goes unrecognised in the elderly (Rabins, 1996), and it is a significant source of concern for families, increases use of medical services and pharmaceutical costs, and impairs immunologic function (Schleifer et al., 1999). It is also one of the main predictors of the risk of suicide among older adults. The World Health Organization indicated in its annual report (WHO, 2006) that depression would be the second cause of disability by 2020, only below that of cardiopathy and higher than cancer or acquired immunodeficiency syndrome (AIDS), since older adults as a population group are particularly vulnerable to disability. The identification of depressive syndromes in the elderly is therefore a health priority, highlighting the necessity of developing and validating economic, simple, and efficacious screening measures for depression in this age group. In this sense, different short versions of the GDS (15, 10, 8, 5 and 4 items) have been proposed, which offer the merits of a simpler administration, easy response format, and economy of time (Sheikh and Yesavage, 1986; Yesavage, 1988; Stiles and McGarrahan, 1998). The GDS-15 appears to have good psychometric properties and adequate performance identifying depression, with a sensitivity up to 91% (D'Ath et al., 1994) for a cut-score of 5 and a specificity up to 81% for a cut-score of 4 (Brown and Schinka, 2005). There are, however, different reasons to be cautious with the use of the shortened forms of the GDS. Other studies have found moderate performance for the GDS- 15 (for example, 67% sensitivity and 73% specificity, for an optimal cut- score of 3, in the Van Marwijk study, 1995), and particularly low positive predictive power values (e.g., 18.4% in Arthur et al., 1999, or 31% in Brown and Schinka, 2005). In a systematic and thorough recent review of the properties of different versions of the GDS in a large number of published studies (Wancata et al., 2006), the sensitivity for the GDS-15 varied between 0.600 and 0.940 (with a mean of 0.805), and the Psychiatry Research 178 (2010) 142–146 ⁎ Corresponding author. Facultad de Psicología, Universidad Autónoma de Madrid, Ciudad Universitaria de Cantoblanco, 28049 Madrid, Spain. Tel.: +34 914974060; fax: +34 914975215. E-mail address: maria.izal@uam.es (M. Izal). 0165-1781/$ – see front matter © 2009 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.psychres.2009.02.018 Contents lists available at ScienceDirect Psychiatry Research journal homepage: www.elsevier.com/locate/psychres