INTRODUCTION:Recent studies suggest that Alzheimer's disease (AD) biomarker disclosure has no discernable psychological impact on cognitively healthy persons. Far less is known about how such results affect symptomatic individuals and their caregivers. METHODS:Randomized controlled trial of 82 mild cognitive impairment (MCI) patient and caregiver dyads (total n = 164) to determine the effect of receiving amyloid positron emission tomography results on understanding of, and perceived efficacy to cope with, MCI over 52 weeks of follow-up. RESULTS:Gains in the primary outcomes were not consistently observed. Amyloid negative patients reported greater perceived ambiguity regarding MCI at follow-up, while moderate and sustained emotional distress was observed in patients, and to a lesser extent, caregivers, of those who were amyloid positive. There was no corresponding increase in depressive symptoms. DISCUSSION:These findings point to the possibility that both MCI patients and caregivers may need emotional support after the disclosure of amyloid scan results.