CBS News highlighted a wave of clinical research that is shifting the focus in Alzheimer’s disease from treating symptoms to preventing onset. Scientists are combining improved biological tests with interventions ranging from lifestyle programs to experimental drugs in trials that enroll people who are still cognitively normal but show signs of future risk.

The recent momentum has two technical drivers. First, blood-based and imaging biomarkers can now detect Alzheimer’s pathology years before memory loss appears. Tests that measure abnormal amyloid or phosphorylated tau in the blood, and established amyloid PET scans, enable researchers to identify asymptomatic individuals likely to develop clinical disease. Second, a new generation of therapies—most visibly anti-amyloid antibodies—has demonstrated the ability to lower brain amyloid and, in some studies of early symptomatic patients, to slow clinical decline. Those findings have encouraged investigators to ask whether intervening even earlier could prevent or delay dementia altogether.

Large prevention trials already under way and planned are testing that idea. Some enroll people with biomarker evidence of amyloid build-up but no cognitive symptoms; others recruit individuals with genetic risk factors or combinations of risk markers. Trials use a range of approaches: targeted biologic drugs, immunotherapies intended to clear or neutralize pathological proteins, and multimodal lifestyle interventions modeled on the FINGER study that combine diet, exercise, cognitive training and vascular risk management.

Early results have been encouraging on several fronts but stop short of declaring victory. Biomarker reductions—lower amyloid on scans or decreased abnormal tau in fluid tests—are being reported before clear clinical benefit can be established. Scientific conservatism is rooted in the long time course of Alzheimer’s: preventing dementia after years of slow pathology requires prolonged follow-up, and the link between short-term biomarker change and long-term cognitive outcomes is still being defined.

Safety and equity are central concerns. Therapies that clear amyloid can produce side effects such as amyloid-related imaging abnormalities, which in some cases cause brain swelling or small hemorrhages and require monitoring with regular MRI scans. Administering such treatments to people who feel healthy raises ethical questions about acceptable risk. There are also daunting cost implications: antibody therapies and frequent imaging are expensive, and widespread screening would expand demand for specialist care, MRI and PET infrastructure. The prospect of identifying large numbers of at-risk but asymptomatic people also brings psychosocial burdens—anxiety, discrimination in employment or insurance, and difficult decisions about long-term planning.

Researchers and policymakers face a complex calculus: how to validate surrogate markers, how long to follow participants to demonstrate meaningful prevention, and how to design trials that include diverse populations historically underrepresented in Alzheimer’s research. If preventive strategies prove effective, early deployment will require systems for equitable screening, counseling and access to treatment.

The cautious optimism reflected in coverage such as CBS News captures the field’s current posture: scientific progress has opened the door to prevention, but proving that door leads to sustained, safe and accessible protection against dementia will take years of rigorous trials and hard policy choices.