Can spanking cause mental illness?

Editor's note: Dr. Jennifer Shu, CNNHealth's Living Well expert doctor, is a practicing pediatrician and mother of two.

Parents often ask me whether spanking is really so bad. After all, they were spanked as kids and they turned out fine. Plus, it's the only thing that will get their child to listen, they say.

Much research has focused on the effects that severe child abuse can have on a person's mental well-being. But a new study published in the July issue of the journal Pediatrics takes a look at the possible link between mental health disorders and harsh physical punishment in the absence of abuse. The findings may persuade parents not to spank at all.

Researchers from Canada found that physical punishment (such as slapping, hitting, pushing and shoving) -- even without child neglect or physical, sexual or emotional abuse -- was linked to mood disorders, anxiety disorders, substance abuse and personality disorders.

When does spanking become abuse?

While it may be true that many of today's parents were spanked as children and are now well-adjusted, previous studies have also shown that those who were spanked are at a higher risk to be depressed; use alcohol; hit their spouse or own children; and engage in violent or criminal behaviors.

Physical punishment doesn't help, it hurts

The American Academy of Pediatrics and the Canadian Paediatric Society discourage spanking and other forms of physical punishment. It is unlawful in 32 countries -- not including the United States or Canada -- for parents and other caregivers to use physical punishment against children.

The new study's lead author, Tracie Afifi, said she believes that physical punishment should not be used on children of any age and that positive parenting strategies should instead be encouraged.

Preferred methods of discipline do not include physical punishment . For example, withholding privileges, using time-outs and offering consequences (for example, "If you throw your toy and it breaks, you won't be able to play with it anymore").

African-Americans most likely to use physical punishment

Dr. Howard Bennett , a pediatrician in Washington and clinical professor of pediatrics at George Washington University School of Medicine, recommends praising children when they are behaving well and using time-outs or a process called " time off ," in which the child must go to another part of the house for as long as it takes to stop the offending behavior and behave normally again.