Behavioural Subtype

Behavioural variant frontotemporal dementia (bvFTD) is the most common form of FTD, accounting for around half of all cases. It primarily affects the frontal lobe of the brain, which are responsible for regulating personality, self-awareness, and social behaviour.

As a result, individuals may experience significant changes in how they act and relate to others. These changes are often gradual and may not be recognised by the person themselves, even though they can be very noticeable to others.

Common features of bvFTD:

  • Individuals may act impulsively, say inappropriate things, or lose their usual social boundaries. Examples include spending money recklessly, making tactless remarks, or acting without concern for others' reactions.

  • Many individuals show reduced initiative or motivation. They may appear withdrawn, fail to complete tasks, or seem content doing very little. These changes are often misinterpreted as depression, though they stem from damage to brain regions involved in goal-directed behaviour.

  • Changes in social awareness and emotional responsiveness are common. Individuals may seem less concerned about others’ feelings, struggle to recognise emotional cues, or behave in ways that appear cold or indifferent.

  • Individuals with bvFTD may develop rigid routines, repeat the same phrases or movements, or engage in repetitive checking or cleaning. They may become unusually focused on certain interests or hobbies, sometimes to an obsessive degree.

  • Alterations in eating habits are frequently reported. These include a preference for sweet or carbohydrate-rich foods, increased appetite or binge eating.

  • Individuals may struggle with planning, organisation, problem-solving, and adapting to change. These difficulties may not be obvious in conversation but can become apparent in daily life, such as when managing finances, navigating unfamiliar situations, or making sound decisions.

These symptoms are linked to shrinkage (atrophy) in the frontal lobes of the brain. In some individuals, the atrophy may also extend to the temporal lobes, which further affects emotional understanding and self-awareness.

These behavioural changes can be distressing and often misunderstood. Understanding that they are caused by a brain condition—not deliberate choices—can help families and carers respond with greater empathy and seek appropriate support.

For more information, on some of the terms used can be found in Glossary.