Harsh parenting practices can have a negative impact on children’s development long-term, according to a new study published in the journal Development and Psychopathology.
It found that children whose parents use strict parenting practices such as shouting or spanking have smaller brain sizes during adolescence. The areas of the brain in which the reduction in size was most significant were the amygdala and prefrontal cortex, which are associated with emotional processing and the development of anxiety and depression.
While it’s already well established that serious child abuse can lead to smaller brains, this is the first time that less severe, often socially acceptable parenting practices have been found to have an impact on the physical anatomy of children’s brains.
What are ‘harsh’ parenting practices?
Repeatedly getting angry, hitting, shaking or yelling at children is linked with smaller brain structures in adolescence according to the new study, which was conducted by Sabrina Suffren, PhD, at Universite de Montreal and the CHU Sainte Justine Research Centre, in partnership with researchers from Stanford University.
“Childhood adversity and anxiety have been associated with increased risk for internalizing disorders later in life and with a range of brain structural abnormalities,” said Suffren, the lead study author. “However, few studies have examined the link between harsh parenting practices and brain anatomy, outside of severe maltreatment or psychopathology.”
Suffren says the harsh parenting practices covered by the study are common and even considered socially acceptable by many people around the world.
"The implications go beyond changes in the brain. I think what's important is for parents and society to understand that the frequent use of harsh parenting practices can harm a child's development. We're talking about their social and emotional development, as well as their brain development."
Emotions and brain anatomy
Serious child abuse (such as sexual, physical and emotional abuse), neglect and even institutionalization have been linked to anxiety and depression later in life.
Previous studies have already shown that children who have experienced severe abuse have smaller prefrontal cortexes and amygdala, two structures that play a key role in emotional regulation and the emergence of anxiety and depression.
In this study, researchers observed that the same brain regions were smaller in adolescents who had repeatedly been subjected to harsh parenting practices in childhood, even though the children did not experience more serious acts of abuse.
"These findings are both significant and new. It's the first time that harsh parenting practices that fall short of serious abuse have been linked to decreased brain structure size, similar to what we see in victims of serious acts of abuse," said Suffren, who completed the work as part of her doctoral thesis at UdeM's Department of Psychology, under the supervision of Professors Francoise Maheu and Franco Lepore.
She added that a study published in 2019 "showed that harsh parenting practices could cause changes in brain function among children, but now we know that they also affect the very structure of children's brains."
Children monitored since birth
One of this study's strengths is that it used data from children who had been monitored since birth at CHU Saint-Justine in the early 2000s by Universite de Montreal's Research Unit on Children's Psychosocial Maladjustment (GRIP) and the Quebec Statistical Institute. The monitoring was organized and carried out by GRIP members Dr. Jean Seguin, Dr. Michel Boivin and Dr. Richard Tremblay.
As part of this monitoring, parenting practices and child anxiety levels were evaluated annually while the children were between the ages of 2 and 9. This data was then used to divide the children into groups based on their exposure (low or high) to persistently harsh parenting practices.
"Keep in mind that these children were constantly subjected to harsh parenting practices between the ages of 2 and 9. This means that differences in their brains are linked to repetitive exposure to harsh parenting practices during childhood," said Suffren who worked with her colleagues to assess the children's anxiety levels and perform anatomical MRIs on them between the ages of 12 and 16.
This study is the first to try to identify the links between harsh parenting practices, children's anxiety and the anatomy of their brains.
