Sunday 17 June 2018

Parenting interventions leave traces behind in DNA

Within today’s developmental psychology, it is assumed that development is an interactive process between the child and the environment. A fascinating aspect is that experiences and circumstances can also have genetic implications for children and grandchildren. 

More and more studies are showing that neglect, abuse or ill-treatment in early childhood leave traces at DNA level.

Parenting and DNA

A recent Canadian study, which focussed on epigenetic processes, revealed that a psychosocial intervention programme aimed at mothers with a tendency to neglect or abuse their children, were helped with parenting support. Furthermore, the researchers see the effects of parenting interventions in the DNA methylation pattern within the genome.
Four hundred mothers and 190 children participated in the long-term study, lasting almost 30 years. These people were from the lower social-economic classes. In 1977, the mothers of these children, who at that time were pregnant for the first time, were divided into two groups. Approximately half of the group of pregnant women received free health evaluation concerning the development of their (at that time) unborn child. Transport to and from the clinic was also funded for these women. 
For a two-year period, the other half received regular home visits and guidance from nurses specialising in parenting and family planning. The number of home visits varied from family to family and ranged from 6 to 30. Thirty years later, the effects of the interventions applied at that time were investigated in the offspring. 


Measurements during the study

Some of the measurements taken during the study involved answering an online questionnaire about the mental health, varying from occurrence of depressions through to problems with addiction, such as drug use. There were few differences between the offspring of the two groups. In other words, in terms of mental health, there was found to be little difference if at the time their mothers attended a consultation clinic for an interim evaluation, or received support from a nurse. 
However, something interesting came to light when the researchers took blood samples. Subtle epigenetic differences were found between the two groups. Interestingly, the correlation between the psychosocial intervention which lasted for two years and the way in which certain genes change their expression and therefore their function. The DNA changes occurred as a result of DNA methylation, a process in which groups of atoms (methyl groups) are added to DNA molecules to change the activity of a DNA segment, without changing the sequence itself. 
The researchers emphasise that (positive) interventions in pregnant women up to and including two years after the birth leave behind traces at genetic level in the offspring. Early interventions therefore have an epigenetic effect. Long-term follow-up studies are needed and should indicate how and whether certain (family) interventions are beneficial from a clinical point of view for the mental health of children and adolescents. 



Kieran J. O'Donnell et al. DNA methylome variation in a perinatal nurse-visitation program that reduces child maltreatment: a 27-year follow-up, Translational Psychiatry (2018). DOI: 10.1038/s41398-017-0063-9