title: The Collateral Source version of the Geriatric Depression Scale: evaluation of psychometric properties and discrepancy between collateral sources and patients with dementia in reporting depression.
abstract: BACKGROUND
  Depression is under-diagnosed and under-treated in older adults. The purposes of this study were to (a) evaluate the psychometric properties of the Collateral Source Geriatric Depression Scale (CS-GDS), (b) compare collateral source scores on the CS-GDS with patient scores on the GDS, and (c) examine factors associated with any discrepancies between the CS-GDS and the GDS.
  
  
  METHODS
  This secondary analysis used data from 132 older adults and their collateral sources attending a geriatric assessment program over a 15-month period. Scores on the 30-, 15-, and 5-item CS-GDS were compared to clinician diagnoses of depression using DSM-IV-TR criteria and patient GDS scores.
  
  
  RESULTS
  The three forms of the CS-GDS had acceptable internal consistency, sensitivity and specificity with recommended cut-off scores of 18, 9 and 3, respectively. Collateral sources reported more depressive symptoms than patients did themselves. Simple regression analysis showed that caregiver burden significantly influenced the discrepancy between CS-GDS scores and GDS scores (β = 0.147; p = 0.004). Functional limitations and collateral relations to the patient were not associated with these discrepancies.
  
  
  CONCLUSIONS
  All three collateral versions had acceptable psychometric properties, which supports the use of the CS-GDS to assess depression in older adults. The CS-GDS provides an important alternative for depression screening with older adults who cannot complete screening tools themselves; however, alternative cut-off scores must be used for high sensitivity and specificity.
authors.affiliation: School of Nursing, The State University of New York, Buffalo, NY, USA.
authors.forename: Yu-Ping
authors.initials: YP
authors.lastname: Chang
authors.forename: Dorothy Farrar
authors.initials: DF
authors.lastname: Edwards
authors.forename: Helen W
authors.initials: HW
authors.lastname: Lach
mesh_terms: D000203:Activities of Daily Living / Q000523:psychology; D000368:Aged; D003704:Dementia / Q000523:psychology*; D003863:Depression / Q000175:diagnosis* / Q000523:psychology; D005260:Female; D015577:Geriatric Assessment / Q000379:methods; D006801:Humans; D008297:Male; D011569:Psychiatric Status Rating Scales / Q000706:statistics & numerical data; D011594:Psychometrics; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity