Introduction: To investigate the structures of the long and short formats of the Center for Epidemiological Studies Depression Scale (CES-D) and validate the impact of the positive affect factor on physical function and psychological stress.
Methods: Data were obtained from 6,537 respondents from WAVE 1 of The Irish Longitudinal Study on Ageing (TILDA), a representative sample of community-dwelling adults aged ≥50 years. Respondents completed the 20 item CES-D. Confirmatory factor analysis was performed to determine the factor structure of the 20-, 10- and two 8-item formats of the CES-D. The positive affect factor from each format was then validated against physical disability (instrumental/activities of daily living-I/ADLs) and perceived stress (4-item perceived stress scale-PSS-4).
Results: Mean and median scores on all formats of the CES-D, ADLs and IADLs were marginally lower than previously reported in other adult populations aged over 50 years. PSS-4 scores were consistent with previous studies. All four versions of the CES-D showed good internally consistency (0.87–0.72). The four factor structure of the CES-D achieved good model fit for the 20 and 10 item versions, with the inclusion of three and two residual covariances, respectively. Both 8-item formats, also displayed a good model fit for the expected three factor structure when one or two of the same residual covariances were included, respectively. The positive affect factors from the long and short forms of the CES-D were closely representative of each other and were negatively correlated with disability and perceived stress.
Conclusion: This study supports the factor structure of the long and short forms of the CES-D in the older adult population of Ireland. We also confirm the reliability and validity of using these forms of the scale to measure Positive Affect, a construct of growing importance to the physical and psychological well-being of older adults.