[Treatable Dementia due to Vitamin B12 and Folate Deficiency].

Vitamin deficiency is one of the major causes of treatable dementia. Specifically, patients suffering from dementia frequentry display low serum levels of vitamin B(12). There is a close metabolic interaction between folate and vitamin B(12). Folate deficiency causes various neuropsychiatric symptoms, which resemble those observed in vitamin B(12) deficiency. This review summarizes, the basic pathophysiology of vitamin B(12) and folate deficiency, its clinical diagnosis, associated neuropsychiatric symptoms such as subacute combined degeneration and dementia, and epidemiological studies of cognitive decline and brain atrophy.