Levels of cholesterol and other fatty molecules in the blood may have an impact on mood and aggression, according to a new study. Studies have shown that male psychiatric patients with low cholesterol (below160 mg/dl) are twice as likely to attempt suicide, and elderly men with low cholesterol are three times as likely to be depressed. And studies in animals have found that monkeys fed a diet low in fat and cholesterol are more aggressive than those fed a normal diet.

The theory is that cholesterol level may influence serotonin, the neurotransmitter in the brain that has been linked to depression. However, it's not yet clear if the low cholesterol actually causes the depression or aggression, or if some other health factor is responsible for both low cholesterol and changes in mood swings.

Psychiatric Services (1997;48:875-876)