Once known as Pick's disease, frontotemporal dementia is overall a less common type of dementia, accounting for just two per cent of cases. However, it is a significant cause in people strong genetic element and often runs in families. Frontotemporal dementia occurs when nerve cells in the frontal and/or temporal lobes of the brain die and the pathways that connect them change.

Over time, the tissue in these lobes shrinks. Frontotemporal dementia has a greater effect on behaviour and personality than memory as the frontal and temporal lobes control behaviour, emotional response and language.

Around 10 per cent of dementia patients suffer from mixed dementia, meaning there is a mixed cause of damage to the brain, e.g. AD and VaD, or AD and DLB. Symptoms are variable and should be treated according to the condition that is thought to be the primary cause. Rarer causes of dementia include alcohol-induced dementia; Down's syndrome; head injury; HIV-related cognitive impairment; Huntington's disease; motor-neurone disease; multiple sclerosis, and Parkinson's disease.