Methylation and Neuropsychiatry

Abstract

Methylation is a process that is required for the normal function of every living cell. S-adenosylmethionine (SAM) is the methyl donor to numerous methyl acceptors such as nucleic acids, proteins, phospholipids, and neurotransmitter amines. The synthesis of SAM is dependent on the normal metabolism of folate and vitamin B₁₂. Deficiencies of these vitamins have been found to reduce central nervous system SAM concentrations; this may impair important methylation processes. Both folate deficiency and vitamin B₁₂ deficiency may cause similar neurological and psychiatric disturbances including depression, dementia, and a demyelinating myelopathy. Treatment with methyl donors has been shown to have a therapeutic effect, which supports a current theory that impaired methylation may be involved in the etiology of some neuropsychiatric disorders. This review of the literature focuses on the biochemical and clinical aspects of methylation and neuropsychiatry.