Being skinny is associated with depression, according to a new study showing the first evidence linking being underweight with low moods.

Experts believe they have found the first evidence of a significant link between being underweight and being depressed.

The research reveals both men and women can be affected by negative thoughts about being too thin, unlike depression among obese people, which predominantly affects women.

However, experts from Seoul National University of Medicine, who led the study, were unable to say whether depression leads to thinness or vice versa.