Parents using smacking as a form of discipline could be affecting their child's mental health, a psychiatrist has claimed.
Dr Ronald W. Pies, professor of psychiatry and lecturer on bioethics and humanity for SUNY Upstate Medical University said smacking can also increase the risk of children developing aggressive or violent behaviour.
The psychiatrist's comments were made in response to US presidential candidate Ted Cruz's admission that he "spanks" his five-year-old daughter when she lies.
Dr Pies wrote in The Conversation: "As a psychiatrist, I can’t ignore the overwhelming evidence that corporal punishment, including spanking - which is usually defined as hitting a child with an open hand without causing physical injury - takes a serious toll on the mental health of children."
Dr Pies said while some parents may think there is nothing wrong with hitting their children after bad behaviour, it usually results in parents' "mounting anger".
Writing his response on this matter, he said the parent is usually stressed to breaking point when they smack and doesn't take into account alternative methods of discipline, such as time out or positive reinforcement.
The doctor said he isn't the first to make this revelation.
He referenced a previous study that showed the "psychological toll on children subjected to corporal punishment is well-documented".
This 2011 study tested the theory that corporal punishment, such as slapping a child for purposes of correcting misbehaviour, is associated with antisocial behaviour and impulsiveness by the child.
The researchers analysed 933 mothers of children aged between two to 14 years old in two small American cities. They found that the strongest relationship between corporal punishment and child behaviour problems occurs among the children of mothers who were frequently impulsive when using corporal punishment.
Following the study the National Association of Pediatric Nurse Practitioners issued a statement that said: "Corporal punishment (CP) is an important risk factor for children developing a pattern of impulsive and antisocial behaviour and children who experience frequent CP… are more likely to engage in violent behaviours in adulthood."
Dr Pies concluded that smacking a child may seem helpful in the short term, but is "ineffective and probably harmful" in the long term, because a child who is often spanked learns that physical force is an acceptable method of problem solving.
Siobhan Freegard, founder of video parenting site Channel Mum agreed with the doctor.
She told HuffPost UK Parents: "Showing your power or forcing someone to do something through violence isn’t acceptable.
"We wouldn’t tolerate it when teaching another adult or even an animal, so why inflict it on a child?
"Some people may try to argue being spanked never did them any harm, but if it leads you to hit your own child, then potentially there is a case that it has.
"There are far more effective ways to teach children right from wrong, starting with setting them an example of how to behave - and that doesn’t include physical violence."
In July 2015, the United Nations advised that parents smacking children should be made illegal in the UK.
In the report, the UN stated the UK should put an end to smacking in "all settings including the home" and "encourage non-violent forms of discipline instead".
They suggested the UK Government should take practical steps to stop parents smacking including legislative measures "where appropriate", with the aim to put an end to corporal punishment throughout the UK.