Amyloid Plaques and Symptoms of Depression Links to Medical Help-Seeking due to Subjective Cognitive Decline

Subjective cognitive decline (SCD) is associated with an increased risk of Alzheimer's disease (AD). However, patients reporting SCD to their general practitioner are not always referred to a memory clinic.

To investigate whether prior history of medical help-seeking is associated with AD biomarker abnormality, worse cognitive performance, and/or depressive symptoms in SCD.

We compared levels of cerebrospinal fluid (CSF) Aβ1 - 42, cognitive performance, and depressive symptoms (15-item Geriatric Depression Scale, GDS-15) between healthy controls (n = 88), SCD with a history of medical help seeking (SCD-HS, n = 67), and SCD non help-seekers (SCD-NHS, n = 44). Cases with evidence of amyloid plaques (CSF Aβ1 - 42 ≤708 ng/l) and symptoms of depression (GDS-15≥6) were determined in both SCD groups.

The SCD-HS group had lower CSF Aβ1 - 42 (p < 0.01), lower word list learning and memory recall (p < 0.0001), and an increased level of depressive symptoms (p < 0.0001) compared to controls and SCD-NHS cases. The SCD-HS group had more cases with symptoms of depression (n = 12, 18%) and amyloid plaques (n = 18, 27%) compared to SCD-NHS (n = 1, 2% and n = 7, 16%, respectively). None of the SCD-HS cases and only one SCD-NHS case had concurrent symptoms of depression and amyloid plaques. The SCD-HS cases showed equal word list learning and memory performance regardless of amyloid status or symptoms of depression.

Medical help-seeking in SCD is associated with an increased risk of AD pathology or symptoms of depression. However, subtle memory deficits are seen in SCD help-seekers, also without amyloid plaques or symptoms of depression.