Comparison Study of the Different Abbreviated Versions of the Geriatric Depression Scale (GDS) in Elderly With Neurocognitive Disorders Attending Social Responses

Depression is the most common mental health problem among older people, both in Portugal and around the world. Due to the fast aging of the world population, depression is a significant problem, with an estimated prevalence between 8% and 16%, which is more common in institutionalized elderly. Several studies have shown the negative consequences of depression in the elderly, which has been associated with higher morbidity and mortality rates, increased use of health services and increased costs. In addition, older people's depression is associated with major disability, chronic health problems, higher suicide rates, dementia and a lower quality of life. However, it is often an unrecognized, and therefore untreated, problem.

Under these circumstances, screening people at risk of depression (people with chronic illness, stroke, dementia, institutionalized or attending social responses, etc.) is a strategy with potential to reduce the impact of depression among the elderly.

One of the most commonly used screening scales for depressive symptoms in elderly is the Geriatric Depression Scale (GDS), a widely known and widely used scale designed specifically for older people. For this reason, it does not include questions related to somatic symptoms, as they lack discriminatory value in older people, because they can be attributed to other physical conditions or the aging process. The original version of the scale is composed by 30 items with a dichotomous response (yes/no) assessing motivation, energy, past and future orientation, mood, cognitive complaints, anxiety and irritability. The GDS scale has good psychometric properties and has been evaluated in a wide range of geriatric populations, institutionalized patients, elderly with chronic health problems, people with dementia, etc. In order to achieve better time efficiency in its administration, the original 30-item scale was abbreviated to a 15-item version. Posteriorly, multiple shorter versions of this scale were developed, composed by one, four, five, ten or twelve items.

The GDS scale has been widely translated and validated worldwide. In Portugal, the GDS-30 was adapted and validated by Pocinho, Farate, Dias, Lee and Yesavage. The versions of GDS-15, GDS-10 and GDS-5 were adapted and validated by Apóstolo and colleagues having demonstrated good psychometric properties and, therefore, potential as a screening tool for depressive symptoms in older people.

The aim of this study is to compare the screening ability of the several validated versions for the Portuguese population of the GDS scale (GDS-30, GDS-15, GDS-10 and GDS-5), as well as to establish their psychometric properties, using a large sample of elderly patients attending social responses addressed to the elderly. This study will allow recommendations on which is the most sensitive GDS version for detecting depressive symptoms by comparing them with other depression screening scales.