The leading group of experts on children鈥檚 health in the United States has reinforced its guidance against spanking, noting that it is ineffective and puts children at an increased risk of developing mental illnesses or substance abuse disorders.

鈥淎versive disciplinary strategies, including all forms of corporal punishment and yelling at or shaming children, are minimally effective in the short-term and not effective in the long-term,鈥 the American Academy of Pediatrics wrote in a on Monday, which updated its guidance on corporal punishment for the first time since 1998.

Parents should be 鈥渆ncouraged and assisted in developing methods other than spanking in response to undesired behaviour,鈥 it added.

Children who are spanked by their parents are at risk of 鈥渘egative behavioural, cognitive, psychosocial and emotional outcomes鈥 similar to those in children who experience physical abuse, the statement says.

These outcomes include aggression, elevated levels of stress hormones and changes to brain development, as well as suicidal behaviour and substance abuse disorders well into adulthood.

The 鈥渋nteraction between spanking and misbehaviour occurs over time,鈥 the statement says. 鈥淓ach negative interaction reinforces previous negative interactions as a complex negative spiral.鈥

The policy statement also cites a study from 2014 that found the effects of spanking were 鈥渢ransient.鈥 Nearly 75 per cent of children surveyed by the study鈥檚 authors had 鈥渞esumed the same behaviour for which they had been punished鈥 within just 10 minutes of being spanked.

The American Academy of Pediatrics recommends that parents reinforce appropriate behaviours, set expectations and use 鈥渢ime outs鈥 when children misbehave.

The Canadian Pediatric Society also strongly discourages parents from spanking their children.

鈥淧hysical punishment can physically and emotionally hurt your child,鈥 the group says on its . 鈥淭here are other, more effective ways to discipline children.鈥

Comforting children by giving them hugs, praising good behaviour and ignoring the 鈥渓ittle things鈥 are among its recommendations for promoting good behaviour.