Improving Diagnosis of Functional Cognitive Impairment in Younger Adults in Primary Care: Validation of Cognitive Screening Tools and the 4-Item Geriatric Depression Scale.

Background: Cognitive decline is classically attributed to organic causes such as dementia; however, depression can play a role in cognitive decline. Objective: To evaluate cognitive screening tools and the 4-item Geriatric Depression Scale (GDS-4) for use in primary care to distinguish cognitive decline secondary to depression. Method: Clinical data collected over 2.5 years for assessed patients in a secondary clinical service for younger adults. Cognitive screening tools (General Practitioner Assessment of Cognition, Addenbrooke’s Cognitive Examination-III, Rowland Universal Dementia Assessment Scale, Salzburg Dementia Test Prediction) and GDS-4 were analyzed for their accuracy to differentiate patients with cognitive decline due to depression from those with subjective cognitive complaints. Results: 180 young adults seen in a memory clinic setting (< 65 years) were included. These individuals either had a diagnosis of depression (n = 46) or no cognitive impairment on assessment (n = 134) despite having subjective cognitive complaints. All used cognitive tools had poor accuracy in differentiating cognitive decline secondary to depression from subjective cognitive complaints. The GDS-4 alone, however, was able to differentiate with high accuracy (AUC = 0.818) individuals who had cognitive problems secondary to depression. Conclusion: Cognitive screening tools used alone are ineffective in discriminating cognitive decline secondary to depression. Incorporating the GDS-4 into the screening process by primary practitioners could facilitate early identification and treatment of depression in younger people, avoiding unnecessary referrals memory services.