Aging has long been considered the main cause of Alzheimer's disease; however, modern research shows that age only increases the risk but is not a direct source of the disease. The disease develops due to specific biological processes that can begin long before old age.
Aging as a Risk Factor, Not a Cause
Age remains a key risk factor: the older a person is, the higher the likelihood of developing the disease. However, during normal aging, the brain retains most of its neurons, although it operates more slowly.
In Alzheimer's disease, a different process occurs — massive death of nerve cells and destruction of the connections between them. This is a pathological process, not a natural continuation of aging.
Individual cases confirm that the disease can manifest at a young age. For example, the scientific literature describes a case of a patient from China whose symptoms began in adolescence, highlighting the complexity and not fully understood nature of the disease.
Genetics and Forms of the Disease
Scientists distinguish two main forms of Alzheimer's disease.
Hereditary Form
A rare variant, accounting for up to 5% of cases, is associated with mutations in the APP, PSEN1, and PSEN2 genes. It manifests at an earlier age and is inherited with a high probability.
This type of the disease is depicted in the film Still Alice, where the character with early Alzheimer's is played by Julianne Moore.
Sporadic Form
The most common form, accounting for up to 95% of cases. It is not linked to a single specific mutation, but the risk increases with certain genetic variants, including APOE-ε4, as well as influenced by lifestyle and environmental factors.
What Happens in the Brain
Two types of proteins play a key role in the development of the disease.
Beta-amyloid accumulates between neurons, forming plaques that hinder signal transmission and cause inflammation.
Tau protein, on the other hand, destroys cells from the inside, forming so-called tangles that disrupt the structure of the neuron and its transport systems.
The combination of these processes leads to the gradual degradation of cognitive functions — memory, thinking, and behavior.
How the Disease is Diagnosed Today
Modern medicine has learned to recognize changes associated with Alzheimer's disease years before obvious symptoms appear.
Among the main methods are positron emission tomography (PET), which visualizes amyloid deposits, as well as blood tests for specific forms of tau protein, such as p-tau217.
Additionally, digital methods are used to track changes in speech, motor skills, and behavioral patterns.
Prospects for Treatment and Prevention
According to estimates from international organizations, by the middle of the 21st century, the number of people with Alzheimer's disease could significantly increase due to the aging population.
The main focus of modern science is shifting from attempts to "cure" the disease to its early prevention. Researchers are studying the mechanisms of brain cell function — microglia and astrocytes, which are responsible for cleaning and protecting the neuronal environment.
Scientists aim not just to eliminate the consequences but to slow down or prevent the very process of destruction. This approach opens up prospects for extending active and conscious life even in the presence of risk factors.
