Smacking children makes them behave aggressive!

There is an increased risk of depression and poor behaviour in adolescents whose mothers are both verbally and physically abusive, and in those whose fathers are either verbally or physically abusive. The risk is highest in teenagers whose parents are violent towards them - for example, if they hit them or threaten them with a gun or a knife.

'The take home point is that the verbal behaviors matter,' Dr Annette Mahoney, a professor of psychology at Bowling Green State University, in Ohio, said.

'It can be easy to overlook that, but our study shows that the verbal hostility is really relevant, particularly for mothers who scream and hit, and for fathers who do either one.'

The researchers say there is a danger of parents becoming trapped in a vicious cycle.

Dr Mahoney explained there is a cyclical element to the problem as teenagers become harder to handle if they have behavioral problems meaning their parents are more likely to resort to threats.