The Dementia Dilemma: If we can detect Alzheimer’s disease earlier, should we?

For decades, dementia was often misdiagnosed and/or diagnosed too late — usually only after symptoms had significantly progressed. Families experience the same frustrating patterns: years of subtle cognitive changes followed by a long, uncertain journey toward diagnosis… with a terminal prognosis to follow.

In the past few years, we have begun to enter a new era of early disease detection, specifically for Alzheimer’s.

New blood tests designed to detect Alzheimer’s-related changes in the brain are improving rapidly. Some experts believe they could transform dementia care by making screening faster, cheaper, and far more accessible. Others worry we are moving toward a future where individuals learn they are at risk and/or battling a disease, with no viable cure or treatment to stop disease progression.

This raises a very important ethical question: If we can identify Alzheimer’s disease and/or other forms of dementia (FTD, Lewy body dementia, etc.) years before symptoms appear, should we before a viable treatment is widely available?

How the New Blood Tests Work…

Alzheimer’s disease is widely believed to be associated with an abnormal buildup of proteins in the brain — primarily amyloid-beta plaques and tau tangles. Traditionally, detecting these changes required either:

• PET brain scans, which are expensive and not widely available
• Spinal taps, which are expensive, invasive, and intimidating for many patients

The newly discovered blood tests work differently. Researchers have developed methods to measure tiny amounts of Alzheimer’s-related proteins circulating in the bloodstream. The most promising tests focus on biomarkers: Amyloid-beta 42/40 ratio, Phosphorylated tau proteins (especially p-tau217 and p-tau181), and Neurofilament light chain (a marker of neurodegeneration).

Many neurologists believe blood-based screening could soon become part of routine memory-care evaluation, given their remarkable accuracy in results comparable to traditional detection tests, such as PET scans and cerebrospinal fluid findings.

Those in Favor of Early Detection…

Individuals in favor of these new early detection tests believe this could transform care by allowing some patients access to newly FDA approved drugs sooner (lecanemab and donanemab), participate in clinical trials, and make important financial, legal, and family decisions while cognition is still relatively intact. Just as importantly, blood tests could expand access beyond large scale hospitals and elite medical centers, into primary care settings.

Those Against Early Detection…

Critics argue we are entering ethically uncertain territory. Alzheimer’s disease still has no cure and not everyone with amyloid buildup will develop dementia. A person could learn they are “at risk” years before symptoms meaningfully impact their life, potentially creating anxiety, depression, or unnecessary medicalization of normal aging.

There are also concerns around privacy and healthcare infrastructure. As predictive brain health testing grows, questions emerge about insurance discrimination, data protection, and whether healthcare systems are prepared to support millions of newly identified patients with counseling, follow-up care, and treatment access.

What makes this new era of dementia diagnosis so significant is that these disease forms are increasingly being viewed not as a late-stage diagnosis, but as a long biological process that may begin decades earlier. Medicine is shifting from reacting to cognitive decline toward predicting it.

The science behind these early detection tests will continue improving, but the bigger challenge may be deciding how society wants to use that knowledge. Will earlier detection ultimately create more solutions towards disease prevention, more confusion and fear, or both.

What do you think?