Trial finds telling healthy volunteers their Alzheimer's biomarker results does no harm

A 341-person randomized trial that told some cognitively normal older adults their amyloid, APOE and hippocampal-volume results, and delayed telling others by a year, found no difference in depression symptoms or cognitive scores between the two groups.

A randomized clinical trial that told some cognitively unimpaired older adults their Alzheimer disease biomarker results right away, and made others wait a year, found no measurable difference in depression symptoms, day-to-day function or cognitive test scores between the two groups, according to results posted on medRxiv by researchers at Washington University in St. Louis. The trial recruited 341 people age 65 and older from the university's Knight Alzheimer Disease Research Center longitudinal aging cohort between 2021 and 2025; 147 were randomized after consenting, and 136 ultimately received results covering their APOE genotype and either amyloid PET or plasma amyloid, plus MRI hippocampal volume, folded into an estimated five-year risk of Alzheimer's dementia.

The question predates the trial by more than a decade. As Alzheimer's research has moved earlier in the disease course, testing cognitively healthy volunteers for amyloid buildup, the APOE4 gene variant and brain shrinkage long before any symptoms appear, researchers and ethics boards have worried that handing over that information could itself cause harm: depression, anxiety, or a self-fulfilling sense of decline. This trial, called WeSHARE and registered with the federal trial database as NCT04699786, was designed specifically to test that worry with a randomized, delayed-start design rather than the observational before-and-after studies that had dominated the field.

Participants who received results within a few weeks (the immediate arm) were compared with those who waited a year (the delayed arm) on annual measures already built into the longitudinal study: the Geriatric Depression Scale, the Clinical Dementia Rating sum of boxes, and a global cognitive composite. Among participants with elevated amyloid, the difference between arms was 0.7 points on the depression scale (95% CI, 0.0 to 1.3), well inside the researchers' predefined threshold of a 4-point change for clinically meaningful decline; 0.0 points on the dementia rating scale (95% CI, -0.1 to 0.1), against a threshold of 0.5; and -0.10 on the cognitive composite (95% CI, -0.25 to 0.06), against a threshold of -0.26. Differences among participants without elevated amyloid were similarly small.

The authors, led by Sarah M. Hartz, describe it as the first randomized trial of its kind and write that the findings support the view that returning these research results does not, in itself, harm cognitively unimpaired volunteers. They also flag its limits directly: the results, they write, may not apply to more diverse populations than the ones enrolled in this study. The paper has been posted on medRxiv and is not yet published in a peer-reviewed journal.

The result does not settle whether disclosure changes what volunteers do afterward, only whether it moved their depression and cognitive scores over the following year, a narrower and more specific question than the trial is sometimes read to answer.