Study: Kids of strict ‘tiger moms’ more likely to develop depression

By Mark Waghorn via SWNS

Kids of strict "tiger moms" are more likely to develop depression, according to new research.

An authoritarian style changes wiring of the brain, say scientists.

Children with overbearing and controlling parents become prone to the world's number one mental illness in adolescence and later life.

"We discovered that perceived harsh parenting, with physical punishment and psychological manipulation, can introduce an additional set of instructions on how a gene is read to become hard-wired into DNA," said lead author Dr. Evelien Van Assche.

"We have some indications that these changes themselves can predispose the growing child to depression.

"This does not happen to the same extent if the children have had a supportive upbringing."

The discovery could lead to a screening program to identify vulnerable individuals.

It goes against the old proverb 'spare the rod, spoil the child' - meaning an undisciplined child will never learn obedience and good manners.

The study was based on 23 Belgian boys and girls aged 12 to 16 who reported harsh parenting - like manipulative behavior, physical punishment or excessive strictness.

They were compared to a similar number of peers matched by age and sex who said their parents were supportive - and gave them autonomy.

Genome mapping showed the former group had increased variation in 'methylation' - which is linked with depression. Many already showed initial, subclinical signs.

Methylation is a normal process which occurs when a small chemical molecule is added to DNA - changing the way instructions are read.

For example, it may increase or decrease the amount of an enzyme produced by a gene.

"We based our approach on prior research with identical twins," Van Assche said.

"Two independent groups found the twin diagnosed with major depression also had a higher range of DNA methylation for the majority of these hundreds of thousands of data points, as compared to the healthy twin."

The Leuven University team measured methylation range at over 450,000 places in the DNA of each subject. It was much higher in those who reported a harsh upbringing.

Van Assche, now at Munster University in Germany, said: "The DNA remains the same.

"But these additional chemical groups affect how the instructions from the DNA are read.

"Those who reported harsher parenting showed a tendency towards depression. We believe this tendency has been baked into their DNA through increased variation in methylation.

"We are now seeing if we can close the loop by linking it to a later diagnosis of depression and perhaps use this increased methylation variation as a marker, to give advance warning of who might be at greater risk of developing depression as a result of their upbringing.

"In this study we investigated the role of harsh parenting - but it's likely any significant stress will lead to such changes in DNA methylation.

"So in general, stresses in childhood may lead to a general tendency to depression in later life by altering the way your DNA is read. However these results need to be confirmed in a larger sample."

Previous research has linked tiger moms to depression, anxiety and aggression in children.

Their offspring struggle to form emotional relationships when they get older - and also have trouble with educational attainment, say scientists.

Professor Christiaan Vinkers, a psychiatrist at Amsterdam University who was not involved in Van Assche's study, said: "This is extremely important work to understand the mechanisms how adverse experiences during childhood have life-long consequences for both mental health and physical health.

"There is a lot to gain if we can understand who is at risk - but also why there are differing effects of strict parenting."

Amy Chua, a professor of law at Yale, coined the term 'tiger mom' in her seminal 2011 book, "The Battle Hymn of the Tiger Mother," in 2011.

Since then, it's been used to describe a parenting style that uses fear and shame, but also one that prioritises familial closeness.

"We show increased variability in DNA methylation is already present in adolescents experiencing adverse parenting and subclinical depressive symptoms, consistent with previous results," Van Assche said.

"These findings can indicate that environmental stress can influence DNA methylation regulatory mechanisms which could lead to a higher overall variability for the chronic stress-exposed group.

"The results fit in the growing evidence that chronic adversity, such as perceived bad parenting, is associated with DNA methylation alterations."

She presented them at a meeting of the European College for Neuropsychopharmacology in Vienna.