Short versions of the geriatric depression scale: A study of their validity for the diagnosis of a major depressive episode according to ICD-10 and DSM-IV

Objective. To determine the validity of short Geriatric Depression Scale (G DS) versions for the detection of a major depressive episode according to I CD-10 criteria for research and DSM-IV. Design. Cross-sectional evaluation of depressive symptoms in a sample of el derly subjects with short GDS versions. Different GDS cutoff points were us ed to estimate the sensitivity, specificity, positive predictive value and negative predictive value for the diagnosis of major depressive episode. In ternal consistency of the scales was estimated with the Cronbach's alpha co efficient. Setting. Mental Health Unit for the Elderly of 'Santa Casa' Medical School in Sao Paulo, Brazil. Participants. Sixty-four consecutive outpatients aged 60 or over who met cr iteria for depressive disorder (current or in remission). Subjects with sev ere sensory impairment, aphasia or Mini-Mental State score lower than 10 we re excluded from the study. Measurements. ICD-IO Checklist of Symptoms; GDS with 15, 10, 4 and 1 items, Montgomery-Asberg Depression Rating Scale (MADRS), ICD-10 diagnostic crite ria for research and DSM-IV diagnostic criteria. Results. The use of the cutoff point 4/5 for the GDS-15 produced sensitivit y and specificity rates of 92.7% and 65.2% respectively, and positive and n egative predictive Values of 82.6% and 83.3% respectively when ICD-10 diagn ostic criteria for major depressive episode were used as the 'gold standard '. Similarly, rates of 97.0%, 54.8%, 69.6% and 94.4% were found when DSM-IV was the comparing diagnostic criteria. Sensitivity, specificity and positi ve and negative predictive values for the cutoff point 6/7 were 80.5%, 78.3 %, 86.8% and 69.2% according to ICD-10, and 84.8%, 67.7%, 73.7% and 80.8% r espectively according to DSM-IV. Intermediate values were found for the cut off point 5/6. The best lit for CDS-10 was the cutoff point 4/5, which prod uced a sensitivity rate of 80.5%, specificity of 78.3%, positive predictive value of 86.8% and negative predictive value of 60.2% according to ICD-10 diagnosis of a major depressive episode. Similarly, rates of 84.8%, 67.7%, 73.7% and 80.8% were found when DSM-IV criteria For major depression were u sed. GDS-4 cutoff point of 2/3 was associated with a sensitivity rate of 80 ,5%, specificity of 78.3%, positive predictive value of 86.8% and negative predictive value of 69.2% when compared to ICD-10. Again, rates of 84.8%, 6 7.7%, 73.7% and 80.8% respectively were found when the criteria used were b ased on DSM-IV. GDS-1 had low sensitivity (61.0% and 63.6% for ICD-10 and D SM-IV respectively) and negative predictive value (56.7% and 67.6% for ICD- 10 and DSM-IV respectively), suggesting that this question is of limited cl inical utility in screening for depression. GDS-15(rho = 0.82), GDS-10 (rho = 0.82) and GDS-4 (rho = 0.81) scores were highly correlated with subjects ' scores on the MADRS. Reliability coefficients were 0.81 for GDS-15, 0.75 for GDS-10 and 0.41 for GDS-4. Conclusion. GDS-15 GDS-10 and GDS-4 are good screening instruments for majo r depression as defined by both the ICD-10 and DSM-IV. The shorter four- an d one-item versions are of limited clinical value due to low reliability an d failure to monitor the severity of the depressive episode. General practi tioners may benefit from the systematic use of short: CDS versions to incre ase detection rates of depression among the elderly. Copyright (C) 1999 Joh n Wiley & Sons, Ltd.