Dementia is a condition usually affecting older people, but dementia symptoms can also occur before the age of 65 years, defined as young or early onset dementia (YOD/EOD).The prevalence of dementia varies with age. Metabolic diseases and genetic causes due to inherited mutations play a more important role in YOD compared to dementia in older people. The diagnosis of YOD is difficult. The presenting symptoms in younger persons are often more heterogeneous than dementia in older persons. There is no curative treatment available for YOD, but relief of behavioral and psychological symptoms in dementia (BPSD), an important strain on the families, may be provide.