Dementia Research Centre


Behavioural variant Frontotemporal Dementia (bvFTD)

Dr Jonathan Rohrer & Dr Jason Warren, Dementia Research Centre

Behavioural variant (bv) FTD is caused by loss of brain cells mainly affecting the frontal and temporal lobes of the brain. These areas control behaviour, personality and complex thinking such as planning or problem-solving.


The first symptom is usually a change in personality or behaviour (which is out of character for the person) – the symptoms may come on very slowly and not be noticed as definitely abnormal at first. The symptoms include the following:

  • Loss of inhibitions or increased extroversion. The person may talk to strangers, make inappropriate remarks in public or be rude or impatient. They may also become aggressive.
  • They may spend money excessively.
  • Apathy or withdrawal from social activities
  • Loss of empathy
  • Changes in sexual behaviour: either more/less or inappropriate interest.
  • People may be very easily distracted.
  • They often develop fixed routines or become obsessive about things, particularly time (‘clock watching’). Some people begin to hoard things.
  • People may also develop a sweet tooth or a preference for unusual foods. They may also overeat leading to a gain in weight or drink excessive amounts of alcohol. In the later stages people with the illness may compulsively put objects in their mouths.
  • Decreased amount of speech or repetitive speech
  • Often the person will be unaware of the true extent of the problems and lack insight.

In the early stages memory is often well maintained on psychological testing (unlike in Alzheimer’s disease) but difficulties in organisation and concentration often lead to an apparent memory problem in daily life and so this is also a common complaint.

Medical tests

Behaviour and aspects of thinking (cognitive functions) will be assessed, initially by a doctor, and often followed by a more detailed assessment by a psychologist. Brain scans can show the loss of brain cells in FTD (shrinkage of the affected parts of the brain) but there is no single test that can specifically diagnose FTD with complete reliability during a person’s lifetime. Furthermore, in the early stages of the disease the scan may look normal. Diagnosis is therefore largely based on clinical judgment and FTD can be confused with other disorders in which there are problems with behaviour (e.g. some psychiatric disorders) and with other dementias. The doctor will often arrange blood tests or other tests (usually including detailed brain scans, in particular MRI, and sometimes a lumbar puncture or other specialised tests) to help confirm the clinical diagnosis and rule out diseases that can produce similar symptoms to FTD.


Unfortunately, there are no medications presently available which can treat the disorder or slow its progression. Treatment therefore focuses on helping people to manage their symptoms, including the behavioural symptoms and treating problems such as mood changes that may contribute to the difficulties that people experience. Medication for behavioural symptoms and mood changes may be needed as the disease progresses.


Behavioural and personality problems deteriorate over time and other aspects of thinking may become affected. There is wide variation in the tempo of the disease between individuals, and some people have a slower form of bvFTD that progresses over a number of years (in some cases over ten). However, in the majority of patients behavioural problems continue to progress such that by around two to five years after the onset of symptoms people generally have problems carrying out their normal activities (particularly where these involve interactions with other people, such as working and driving) and will need extra care and support.