The goal of this multicenter prospective observational cohort study is to better understand the clinical, neuropsychological, and biological characteristics of individuals attending Brain Health Services (BHS) in the Lombardy region. The study focuses on adults with subjective cognitive decline (SCD), functional cognitive disorder (FCD), or "well worried" individuals without objective cognitive impairment.

The main questions it aims to answer are:

• What clinical, cognitive, and biological differences exist between individuals who are positive versus negative for Alzheimer's disease (AD) plasma biomarkers (p-tau217) at baseline?
• What factors predict positivity to AD biomarkers at baseline?
• How does communication of biomarker results (risk disclosure) affect psychological well-being shortly after receiving results?
• What factors predict longitudinal changes in AD biomarkers over 5 years?
• Do baseline biomarkers predict the development of mild cognitive impairment (MCI) or dementia during follow-up?

Participants will:

• Undergo standard clinical evaluation at their local BHS
• Provide blood samples for plasma biomarker analysis (e.g., p-tau217, GFAP, NfL, ApoE)
• Undergo neuropsychological testing and cognitive screening
• Complete questionnaires assessing psychological impact and risk perception (before and after biomarker disclosure)
• Undergo additional center-specific procedures when clinically indicated (e.g., MRI, lumbar puncture, polysomnography)
• Be followed annually for 5 years

The study plans to enroll approximately 1000 participants across multiple BHS in Lombardy and will follow them for a total duration of 7 years. The results will help clarify the role of biomarkers in early cognitive complaints and support the development of preventive strategies within BHS.

Inclusion Criteria:

• Adults (≥18 years)
• Diagnosis of SCD, FCD, or "well worried" individuals without objective cognitive impairment
• Evaluation at one of the Lombardy BHS
• Ability to provide written informed consent

Exclusion Criteria:

• Diagnosis of mild cognitive impairment or dementia at baseline visit
• Enrollment in another interventional study with an expected effect on cognition
• Pregnancy or breastfeeding

Subjects accessing BHS in Lombardy with SCD, FCD or "well worried" individuals without objective cognitive impairment

De-identified individual participant data underlying the results reported in publications (including demographic, clinical, neuropsychological, biomarker, and imaging-derived variables) will be made available.

Beginning 12 months after primary publication and ending 5 years thereafter.

Data will be available to researchers who provide a methodologically sound proposal, subject to approval by the study steering committee and signing of a data use agreement.