What is homocysteine?

Homocysteine is a sulphur-containing amino acid that is derived from the diet. As folate is needed to metabolise homocysteine, and vitamin B12 helps keep homocysteine levels low, people who are deficient in these vitamins may have increased levels of homocysteine. Homocysteine is involved in a large number of processes in the central nervous system, including alteration in glutamatergic neurotransmission which has been implicated in many psychiatric disorders. Increased homocysteine can also promote vasulotoxic effects which contribute to a range of medical disorders, including cardiovascular disease; a common comorbid condition in people with bipolar disorder.

What is the evidence for changes in homocysteine in people with bipolar disorder?

High quality evidence suggests a large effect of increased homocysteine in people with bipolar disorder during a mania phase, and a small effect during euthymia when compared to controls without bipolar disorder. The effect during euthymia was not influenced by patients’ age or sex, and there were insufficient studies to assess the effect of age or sex during mania.

Only one study assessed homocysteine levels during bipolar depression, and found no differences with controls.

July 2020

Last updated at: 5:19 am, 10th July 2020
To view documentation related to this topic download the files below
Fact Sheet Technical Commentary

NeuRA Libraries

Title Colour Legend:
Green - Topic summary is available.
Orange - Topic summary is being compiled.
Red - Topic summary has no current systematic review available.