Women who have higher levels of appetite-control hormone leptin tend to have fewer symptoms of depression, reveals study.
It also found that this apparent inverse relationship was not related to body mass index (BMI).
"Animal data suggest that leptin may reduce anxiety and improve depression. Our study in women suggests that leptin may indeed have antidepressant qualities," said lead author Elizabeth Lawson, MD, of Massachusetts General Hospital and Harvard Medical School in Boston.
Leptin, the product of fat cells, is low in thin women and high in obese women, she said.
Lawson and her co-workers studied the relationship between leptin levels and symptoms of anxiety and depression in 64 women. Fifteen of the women had anorexia nervosa, 12 were normal weight with hypothalamic amenorrhea, 20 were normal weight and in good health, and 17 were overweight or obese but still healthy.
All subjects were asked questions to assess symptoms of depression and anxiety, with high scores indicating more symptoms. Besides measuring leptin levels in the blood, the researchers assessed the women's BMI, a measure of weight for height.
They found that higher leptin levels were linked to decreased symptoms of anxiety and depression. The relationship between leptin and depression symptoms was independent of BMI. This finding indicates that leptin may mediate symptoms of depression and that this effect is not a function of low weight, said Lawson.
The results were presented recently at The Endocrine Society's 93rd Annual Meeting in Boston.