Types of young onset dementia

Alzheimer’s disease is the most common form of dementia in older and younger adults, accounting for around 60% of diagnoses in the UK. It is caused by a build-up of proteins in the brain which affect how the brain cells transmit messages. Over time, more and more brain cells become damaged, which is why it is known as a progressive disease. The most noticeable symptom is typically memory loss, but every person experiences dementia differently.

Vascular dementia is a form of dementia that occurs when the brain does not receive enough blood supply, stopping the brain from carrying out its normal functions. It is caused by damage or disease to the blood vessels in the brain, often as the result of the damage from a stroke. Vascular dementia can also result from other conditions that affect the supply of blood to the brain, like diabetes, high blood pressure and heart disease.

CADASIL (cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy) is a disease of the blood vessels in the brain. It is a rare genetic form of vascular dementia and symptoms can include migraines, repeated strokes, loss of mental abilities, seizures and apathy. The symptoms typically start when a person is in their mid-30s. CADASIL is caused by a genetic mutation in the NOTCH3 gene, usually inherited from a parent who has a 50% chance of passing on the mutated copy of the gene.

Frontotemporal dementia (FTD) is caused by damage to the lobes at the front and/or sides of the brain. It is much more common in younger people with dementia than in older people. FTD is most often diagnosed in people between the ages of 45 and 65 and often causes changes in personality, behaviours and movement.

Dementia with Lewy bodies is caused by the build-up of very small protein deposits (Lewy bodies) in the brain. Lewy bodies also cause Parkinson’s disease and research suggests that around one-third of people with Parkinson’s eventually develop dementia. Symptoms can include hallucinations and varying levels of alertness. People can also develop the features of Parkinson’s disease like slower movement, stiffness and trembling limbs.

Parkinson’s is a condition in which a part of the brain called the substantia nigra loses nerve cells. This loss of nerve cells results in a reduction of a substance called dopamine which is important for the regulation of movement of the body. As the dopamine levels decrease the person’s movements become slower. Most people with a diagnosis of Parkinson’s do not go on to develop dementia, however research suggests that around one third of people will. This is known as ‘Parkinson’s with dementia.’

Posterior cortical atrophy (PCA), also known as Benson’s Syndrome, is the degeneration of the cells at the back or posterior of the brain. People with PCA will often first experience problems with their sight, rather than memory. This is because their brain is having trouble interpreting the information sent to it by the eyes. PCA is a rare form of dementia that people often develop between the ages of 50 and 65.

Alcohol-related brain damage is caused by drinking too much alcohol on a regular basis over several years which causes direct damage to the nerve cells in the brain. It can also be caused by a lack of thiamine (vitamin B1), head injuries and a poor diet. Alcohol-related brain damage covers a range of conditions including alcohol-related dementia and Wernicke–Korsakoff syndrome. People diagnosed with ARBD tend to be in their 40s and 50s.

Symptoms will depend on the cause of the ARBD, but they can include problems with organisation, problem solving, attention span and controlling emotions. They may also include changes in personality, difficulties learning new skills and disorientation.

Mixed dementia is when an individual is diagnosed with not just one but two types of dementia, such as Alzheimer’s disease and vascular dementia. A person with mixed dementia would experience a mixture of the symptoms associated with both the types of dementia they have been diagnosed with.