SAN FRANCISCO, July 30 (Xinhua) -- Researchers from Stanford University have found that people suffering depression have very low blood levels of a substance called acetyl-L-carnitine, a new study shows Monday.
Natalie Rasgon, a professor of psychiatry and behavioral sciences at Stanford, and her team have conducted extensive experiments on animals, and discovered a deficiency of acetyl-L-carnitine was associated with depression-like behavior, the first rigorous indication that the link between acetyl-L-carnitine levels and depression may apply to human beings.
The findings, which were published online Monday in the Proceedings of the National Academy of Sciences, suggest that acetyl-L-carnitine plays a special role in the brain, where it works at least in part by preventing the excessive firing of excitatory nerve cells in brain regions
Acetyl-L-carnitine is a crucial mediator of fat metabolism and energy production throughout the body. It is either naturally produced in human body or available in drugstores as a nutritional supplement.
The scientists examined a group of men and women, aged between 20 and 70, who have been diagnosed with depression and screened with a detailed questionnaire or assessed clinically.
Twenty-eight of them were judged to have moderate depression, and 43 had severe depression. Their blood samples showed they had substantially lower levels of acetyl-L-carnitine, regardless of age. The lowest levels of acetyl-L-carnitine were in patients with treatment-resistant depression.
According to the research, the degree of acetyl-L-carnitine deficiency reflected both the severity and age of onset of depressive disorder, and the decrease in acetyl-L-carnitine was more significant in patients with a history of treatment-resistant depression.
Among them, childhood trauma including abuse, neglect, poverty or exposure to violence, and, specifically being female, are linked to reduced levels of acetyl-L-carnitine.
Those patients, who account for about 25 percent and 30 percent of all people with depression, are in bad need of effective pharmacological interventions, Rasgon said.
She said depression is the top reason for absenteeism at work and one of the leading causes of suicide, and the disorder affects about 8 percent to 10 percent of the total population in the Unite States.
The findings of the Stanford scientists could open a new way to a new class of antidepressants that could have no side-effects and faster-acting functions than existing drugs today.
