Differential item functioning of the Geriatric Depression Scale in an Asian population

Area of Science:

• Geriatric Psychiatry
• Psychometrics
• Epidemiology

Background:

• The Geriatric Depression Scale (GDS) is a common tool for screening major depressive disorder (MDD) in older adults.
• Screening tools require validation across different cultural contexts to ensure accuracy.
• Differential item functioning (DIF) analysis is crucial for identifying item bias in diverse populations.

Purpose of the Study:

• To examine differential item functioning (DIF) in the Geriatric Depression Scale-15 (GDS-15).
• To assess DIF related to age, gender, ethnicity, and chronic illness in a Singaporean elderly population.

Main Methods:

• Utilized the GDS-15 and Structured Clinical Interview for DSM-IV diagnosis of MDD.
• Employed Multiple Indicator Multiple Cause (MIMIC) latent variable modeling.
• Analyzed data from 4253 non-institutionalized community-dwelling elderly subjects aged 60+.

Main Results:

• Identified significant DIF for 8 GDS-15 items.
• DIF was associated with age, gender, ethnicity, and chronic illness.
• Specific items showing DIF included those related to activities, interests, fear, social preference, memory, life satisfaction, worthlessness, energy, and hopelessness.

Conclusions:

• The GDS-15 exhibits DIF in a heterogeneous Singaporean population.
• Awareness of DIF supports the GDS-15's use in diverse groups.
• Findings guide the development of culturally adapted or abbreviated scales.