WASHINGTON — Children who are spanked frequently at age three are more likely to be aggressive when they're five, a recent study has found.

The results reinforce earlier studies which have found that children who are spanked have lower IQ scores and that frequent spanking has been linked to anxiety and behavior problems and higher risk of violent or criminal behavior, depression and excessive alcohol use.

Researchers surveyed 2,500 mothers across the United States.

Nearly half said they had not spanked their three-year-old in the past month, while 27.9 percent said reported one or two spankings and 26.5 reported spanking more than twice.

Two years later, the mothers who had spanked their children more frequently reported higher levels of aggression such as arguing, screaming, fighting, destroying things, cruelty or bullying in their five-year-olds.

The results held true even when researchers accounted for potentially confounding factors such as the presence of aggression within the family and parental stress, depression and drug or alcohol use.

"There are ways to discipline children effectively that do not involve hitting them and that can actually lower their risk for being more aggressive," said lead author Catherine Taylor of the Tulane University School of Public Health.

"So the good news is, parents don't have to rely on spanking to get the results that they want," Taylor said in a press release.

"If they avoid spanking but instead use effective, non-physical types of discipline, their child has a better chance of being healthier, and behaving better later."

The American Academy of Pediatrics strongly opposes striking children for any reason and recommends time outs, withholding privileges and logical consequences like taking putting toys away for the rest of the day if a child does not pick them up.

The study, which will be published in the May issue of the journal Pediatrics, was released on Monday.