The Geriatric Depression Scale (GDS) is a 30-item self-report measure designed to assess and screen depressive symptoms in older adults. Developed in response to the limitations of existing depression screeners for this population, the GDS includes items specifically tailored to older adults, with relatively few somatic items to avoid over-reporting due to medical conditions. The GDS is formatted to be straightforward and brief, allowing respondents to complete it in less than 10 minutes. The 30 items were selected based on their highest correlation with the total score. The GDS uses a simple yes/no format, with each item scored as one point for a depressive response. Total scores range from 0 to 30, with scores of 0–9 indicating normal mood, 10–19 indicating mild depressive symptoms, and 20–30 indicating severe depressive symptoms. The GDS is free to use and available online. Research indicates that the GDS has excellent reliability, with reliability coefficients ranging from 0.85 to 0.94. Validity studies show that the GDS has good criterion validity, with high sensitivity and specificity in identifying depression. Convergent validity is supported by high correlations with other depression measures, while discriminant validity is demonstrated by the lack of correlation with constructs such as cognition and pain. Alternate forms of the GDS include the GDS-SF (15 items) and GDS-15, which have mixed validity in different populations. The GDS-SF is valid for use among young and middle-aged adults and has acceptable reliability and validity. The GDS-15 may be useful in detecting changes in moderate levels of depression but is not always an acceptable substitute for the full GDS.The Geriatric Depression Scale (GDS) is a 30-item self-report measure designed to assess and screen depressive symptoms in older adults. Developed in response to the limitations of existing depression screeners for this population, the GDS includes items specifically tailored to older adults, with relatively few somatic items to avoid over-reporting due to medical conditions. The GDS is formatted to be straightforward and brief, allowing respondents to complete it in less than 10 minutes. The 30 items were selected based on their highest correlation with the total score. The GDS uses a simple yes/no format, with each item scored as one point for a depressive response. Total scores range from 0 to 30, with scores of 0–9 indicating normal mood, 10–19 indicating mild depressive symptoms, and 20–30 indicating severe depressive symptoms. The GDS is free to use and available online. Research indicates that the GDS has excellent reliability, with reliability coefficients ranging from 0.85 to 0.94. Validity studies show that the GDS has good criterion validity, with high sensitivity and specificity in identifying depression. Convergent validity is supported by high correlations with other depression measures, while discriminant validity is demonstrated by the lack of correlation with constructs such as cognition and pain. Alternate forms of the GDS include the GDS-SF (15 items) and GDS-15, which have mixed validity in different populations. The GDS-SF is valid for use among young and middle-aged adults and has acceptable reliability and validity. The GDS-15 may be useful in detecting changes in moderate levels of depression but is not always an acceptable substitute for the full GDS.