High Prevalence of Stress and Low Prevalence of Alzheimer Disease CSF Biomarkers in a Clinical Sample with Subjective Cognitive Impairment.

BACKGROUND/AIMS: Subjective cognitive impairment (SCI) is a trigger for seeking health care in a possible preclinical phase of Alzheimer's disease (AD), although the characteristics of SCI need clarification. We investigated the prevalence of psychosocial stress, depressive symptoms and CSF AD biomarkers in SCI and MCI (mild cognitive impairment).

METHODS: Memory clinic patients (SCI: n = 90; age: 59.8 ± 7.6 years; MCI: n = 160; age: 63.7 ± 7.0 years) included in the Gothenburg MCI study were examined at baseline. Variables were analyzed using logistic regression with SCI as dependent variable.

RESULTS: Stress was more prevalent in SCI (51.1%) than MCI (23.1%); p < 0.0005. SCI patients had more previous depressive symptoms (p = 0.006), but showed no difference compared to MCI patients considering current depressive symptoms. A positive CSF AD profile was present in 14.4% of SCI patients and 35.0% of MCI patients (p = 0.001). Stress (p = 0.002), previous stress/depressive symptoms (p = 0.006) and a negative CSF AD profile (p = 0.036) predicted allocation to the SCI group.

CONCLUSION: Psychosocial stress is more prevalent in SCI than previously acknowledged. The high prevalence and long-term occurrence of stress/depressive symptoms in SCI in combination with a low prevalence of altered CSF AD biomarkers strengthens the notion that AD is not the most likely etiology of SCI.