How to Calculate Geriatric Depression Scale
What is Geriatric Depression Scale?
The Geriatric Depression Scale (GDS-15) Calculator scores 15 yes/no questions designed specifically for older adults to screen for depression, avoiding somatic symptoms that overlap with normal aging or medical illness.
Formula
GDS-15 Score = Count of depressive responses (10 items: Yes=1; 5 items reverse-scored: No=1); Range: 0-15
- TS
- Total GDS-15 Score (points (0-15)) — Sum of depressive responses indicating depression severity
- Ri
- Item Response (0 or 1) — Binary depressive indicator per item after applying reverse scoring
- SL
- Severity Level (category) — Normal (0-4), Mild (5-8), Moderate (9-11), or Severe (12-15)
Step-by-Step Guide
- 1Answer 15 yes/no questions about how you have felt over the past week
- 2Items 1, 5, 7, 11, 13 are reverse-scored (No = 1 point indicates depression)
- 3All other items: Yes = 1 point indicates depression
- 4Total score: 0-4 normal, 5-8 mild depression, 9-11 moderate depression, 12-15 severe depression
Worked Examples
Input
78-year-old, endorsed 7 depressive responses
Result
GDS-15 score: 7/15 — mild depression range (5-8). Warrants clinical evaluation and possible treatment initiation.
Input
82-year-old, endorsed 12 depressive responses
Result
GDS-15 score: 12/15 — severe depression range (12-15). Requires prompt clinical assessment and treatment.
Common Mistakes to Avoid
- ✕Failing to reverse-score items 1, 5, 7, 11, and 13 where "No" indicates the depressive response
- ✕Using the GDS-15 with patients who have moderate-to-severe dementia — the tool requires sufficient cognitive function to answer reliably
- ✕Interpreting the GDS as diagnostic rather than as a screening tool that prompts further clinical evaluation
Frequently Asked Questions
Why use the GDS instead of the PHQ-9 for older adults?
The GDS was specifically designed for elderly patients and uses simple yes/no questions without somatic items (sleep, appetite, fatigue) that overlap with normal aging and medical conditions, making it more specific for depression in this population.
Can the GDS be used with dementia patients?
The GDS-15 is valid for patients with mild cognitive impairment and mild dementia. For moderate-to-severe dementia, observational scales like the Cornell Scale for Depression in Dementia are more appropriate.
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