Immediate reactions to amyloid PET disclosure in Japanese older adults without dementia

Abstract

INTRODUCTION: Amyloid positron emission tomography (PET) has become increasingly important for detection of early Alzheimer's disease (AD) and eligibility for emerging disease-modifying therapies. While North American and European studies report limited short-term psychological harm following disclosure of amyloid status in asymptomatic individuals, evidence in non-North American and European contexts is scarce. We evaluated the immediate psychological impact of amyloid PET disclosure in a large Japanese cohort without dementia. METHODS: We analyzed data from 630 cognitively unimpaired Clinical Dementia Rating global score (CDR-GS of 0, 70%) or mild cognitive impairment (CDR-GS of 0.5, 30%) participants 50–85 years of age enrolled in the Japanese Trial-Ready Cohort onsite study across seven centers between July 2020 and January 2024. Amyloid PET positivity was defined by visual read or Centiloid ≥12. Psychological outcomes—Future Time Perspective (FTP), and Concerns about AD—were assessed immediately before and after disclosure; Impact of Event Scale (IES) was also measured via telephone 1–3 days post-disclosure. Mixed-effects Poisson and linear regression models, adjusted for site, participant, and baseline covariates, evaluated the effects of PET positivity on post-disclosure outcomes. RESULTS: Twenty-six percent of participants were PET positive. PET-positive individuals experienced greater distress (median IES 8 vs 3) compared with PET-negative peers, whereas FTP improved similarly irrespective of PET status. Concerns about AD increased modestly in PET-positive participants (+4.8%) but decreased in PET-negative individuals (−5.5%; interaction p < 0.001). Female sex and higher baseline depression and anxiety predicted larger distress responses. DISCUSSION: Consistent with North American and European findings, amyloid PET disclosure in this Japanese cohort was generally well-tolerated, eliciting only modest increases in distress and concerns among PET-positive individuals. These results support the feasibility and ethical acceptability of structured disclosure protocols across cultural settings and highlight the importance of tailored counseling for at-risk subgroups. Highlights: Immediate impact of amyloid disclosure in a Japanese cohort without dementia. Amyloid-positive individuals had higher distress (Impact of Event Scale) after disclosure. Future Time Perspective improved similarly regardless of amyloid positron emission tomography (PET) results. Concerns about Alzheimer's disease slightly rose in PET-positive participants. Female sex and higher baseline depression and anxiety predicted larger distress.