A study conducted with 871 middle age Finnish men found a close relationship with high homocysteine levels and depression. Those with higher homocysteine levels showed a higher incidence of heart attacks as well. A similar study conducted in USA among younger population found no relationship between homocysteine and depression. It is good to point out that 11.9 micro moles per liter or more is considered high levels of homocysteine... in other words we do not know what is the normal range among younger populations. Low levels of folic acid and vitamin B12 has been linked with depression as well. The mechanism of why high levels of homocysteine and low levels of vitamin B12 and folic acid can cause depression is not well understood but it is believed that a problem with monoamine metabolism and/or methylation can be behind depression and higher concentrations of homocysteine.

Homocysteine is an inflammation marker and has been linked with cardiovascular accidents.

The American Journal of Nutrition 2004;80:1574-8