Strict Parenting May Hardwire Depression Into a Child’s DNA

The researchers found that strict parenting can affect the way the body reads DNA.

The way the body reads the children’s DNA might change as a result of strict parenting. These alterations may become ‘hard-wired’ into the DNA of children who perceive their parents to be harsh, raising their biological risk for depression in adolescence and later life.

Dr. Evelien Van Assche recently presented the work at the European College of Neuropsychopharmacology (ECNP) Congress in Vienna.

She elaborates on her work, “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. 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.”

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The researchers from the University of Leuven in Belgium chose 21 adolescents who reported good parenting (for example, supportive parents who give their children autonomy) and compared them to 23 adolescents who reported harsh parenting (for example, manipulative behavior, physical punishment, excessive strictness). All of the adolescents were between the ages of 12 and 16, with a mean age of 14 for both groups. Both groups included 11 adolescents who were males, meaning that the two groups were equal in terms of age and gender distribution. Many of those who had been subjected to harsh parenting displayed early, subclinical signs of depression.

The researchers then analyzed the range of methylation at over 450,000 places in each subject’s DNA and discovered that it was significantly increased in those who experienced a harsh upbringing. Methylation is a natural process in which a small chemical molecule is added to the DNA, altering the way the instructions encoded in your DNA are read: for example, methylation may increase or reduce the amount of an enzyme produced by a gene. Increased methylation variation has been linked to depression.

Evelien Van Assche said “We based our approach on prior research with identical twins. Two independent groups found that 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.”

Dr. Van Assche (now working at the University of Munster, Germany) continued, “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, and we believe that 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.”

She adds, “In this study, we investigated the role of harsh parenting, but it’s likely that 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.”

Commenting, Professor Christiaan Vinkers, Department of Psychiatry, Amsterdam University Medical Centre, said: “This is extremely important work to understand the mechanisms of 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.”

Reference: 35th Congress of the European College of Neuropsychopharmacology (ECNP)

Professor Vinkers was not involved in this work, this is an independent comment.

The study was funded by the KU Leuven Research Fund.