Being overweight can cause depression even when no other health problems exist, according to a study released Tuesday by the University of Exeter.

A team led by researchers from the University of Exeter and the University of South Australia, analyzed UK Biobank data from more than 48,000 people with depression and compared them to another group of more than 290,000 people.

While it has long been known that depression is more common in obesity, the team concluded that higher body mass index (BMI) can cause depression in itself, even in the absence of other health problems.

"Our robust genetic analysis concludes that the psychological impact of being obese is likely to cause depression. This is important to help target efforts to reduce depression, which makes it much harder for people to adopt healthy lifestyle habits," said Dr Jess Tyrrell, of the University of Exeter Medical School.

The team tested their results in a second large-scale cohort, using data from the Psychiatric Genomics Consortium. They reached the same conclusion, verifying their results.

The study has been published in the International Journal of Epidemiology.