What Causes Alzheimer's disease? 5 Possible Causes

Alzheimer’s disease can occur due to genetic mutations, the accumulation of abnormal proteins in the brain, a reduced release of acetylcholine by the neurons, or an HSV-1 infection. However, the causes of this condition continue to be studied and discussed.

Alzheimer’s disease is a type of dementia that causes cellular death of the neurons, It compromises the way neurons work and how they function, which can lead to changes to memory, attention, language, orientation, perception, logic and thinking. 

If you suspect you may have symptoms of Alzheimer’s, it is important to consult a neurologist. The treatment may involve anticholinergic medication, like rivastigmine or memantine, as well as physiotherapy and occupational therapy. 

Possible causes

The most studied causes of Alzheimer’s disease are: 

1. Genetics

There have been 20 geneticm mutations discovered that affect cellular function in the brain. These mutations stimulate inflammation and alter metabolism of substances, which increases the risk for Alzheimer’s. 

It is believed that the more changes to DNA that are noted, the higher the risk for developing this disease. Although these changes can emerge randomly, they may also be passed down from parent to child.

It is known that APP, PSEN1 and PSEN2 gene are responsible for rare types of Alzheimer’s within the same family, particularly in people between the ages of 40 and 50. In these cases, there is a 50% chance that the person will transmit the disease to their child.  

2. Protein accumulation in the brain 

People with Alzheimer’s have been observed to have a higher accumulation of proteins in the brain. These proteins, referred to as beta-amyloid and Tau proteins, cause neuron inflammation, inorganization and destruction, particularly in the hippocampus and cortex of the brain. 

It is known that these changes may be influenced by the genes above, although the exact cause for why proteins build up is not completely known. How to prevent this is also not known, which is why a cure for Alzheimer’s has not been found yet. 

3. Reduced acetylcholine levels 

Acetylcholine, a neurotransmitter released by neurons, plays an important role in brain functions like learning, memory and attention. Levels are typically decreased in people with Alzheimer‘s. 

It is believed that losing neurons that release acetylcholine may be responsible for some the symptoms of this condition, however the exact cause of symptoms is not known.

Therefore, treatment for Alzheimer’ usually involved medications that increase acetylcholine in the brain, like donepezil, galantamine and rivastigmine. 

4. Environmental risks 

In addition to genetic changes, there are also characteristics in a person‘s health history that are associated with changes to how the brain functions, which can lead to a higher risk for Alzheimer’s. These risks include:

  • Smoking
  • Sedentary lifestyle
  • High cholesterol levels and atherosclerosis 
  • Age over 65 years old
  • History of stroke or brain trauma from an accident or sports 
  • Hearing loss
  • Depression 

For these reasons, it is important to adopt healthy lifestyle habits and to prioritize exercise and a diet rich in vegetables and low in processed foods.

5. Herpes virus 

Some studies suggest that another possible cause of Alzheimer’s is the infection that causes oral herpes, HSV-1 (herpes simplex virus 1). It can remain dormant in the body and become activated during periods of stress or when the immune system is weakened. 

It is believed that people that carry the APOE4 gene and the HSV-1 virus have a higher chance for developing Alzheimer’s., as the immune system becomes weaker with old age and the virus can reach the brain. This can lead to an accumulation of abnormal proteins in the brain.

Researched have studied different treatment options with viral medications to delay certain Alzheimer’s symptoms and to cure this disease. 

Which doctor should I see?

If you suspect you may have Alzheimer’s, you are advised to consult a neurologist. This doctor can perform specific tests to evaluate memory and logic, as well as prescribe tests like an MRI and a neuropsychological exam to confirm a diagnosis. 

The neurologist may also orders bloodwork like vitamin levels and thyroid hormones to rule out other conditions that can cause memory changes (like hypothyroidism and vitamin B12 deficiency). 

Treatment options

Alzheimer's disease is not curable, however treatment can delay symptoms The doctor may prescribe medications like donepezil, galantamine, rivastigmine, or memantine.

The doctor may also prescribe physiotherapy, occupational therapy and psychotherapy, depending on the difficulties and symptoms each patient presents with.