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.