Unhealthy and unhappy: Mental toll of troubled relationships

The UQ School of Public Health study found many victims of intimate partner violence at 21 showed signs of mental illness at the age of 30, with women more likely to develop depression and men varying anxiety disorders.

Intimate partner violence classifies physical abuse as pushing, shoving and smacking.

UQ researcher Emeritus Professor Jake Najman said the team also found equal levels of abuse by men and women.

"The number of men and women who experience intimate partner violence is very similar, leading us to believe couples are more likely to abuse each other," Professor Najman said.

"People generally don't end up in the hospital or a shelter, but there is a serious mental burden from this type of abuse."

The research showed defacto couples and those from lower socio-economic backgrounds were more likely to be involved in these types of abusive relationships.

Emotional abuse involves comments that make the person feel worthless.

Then there is harassment -- a constant and distressing nagging that may have long-term consequences for those on the receiving end.

"It also raises the question, to what extent is this type of violent behaviour not just a characteristic of the relationship the couple has with each other, but with other people around them and possibly their children," Professor Najman said.

"There is a range of treatment and counselling programs available for couples and families to try and improve the way they relate to one another."