The study published in the journal Psychological Medicine seeks to better understand the mechanisms that explain how difficult experiences disrupt our response to stressful situations. “Many people think that our genes are immutable; however this study suggests that environment, even the social environment, can affect their functioning. This is particularly the case for victimization experiences in childhood, which change not only our stress response but also the functioning of genes involved in mood regulation,” says Isabelle Ouellet-Morin, lead author of the study.
A previous study by Ouellet-Morin, conducted at the Institute of Psychiatry in London (UK), showed that bullied children secrete less cortisol—the stress hormone—but had more problems with social interaction and aggressive behaviour. The present study indicates that the reduction of cortisol, which occurs around the age of 12, is preceded two years earlier by a change in the structure surrounding a gene (SERT) that regulates serotonin, a neurotransmitter involved in mood regulation and depression.
To achieve these results, 28 pairs of identical twins with a mean age of 10 years were analyzed separately according to their experiences of bullying by peers: one twin had been bullied at school while the other had not. “Since they were identical twins living in the same conditions, changes in the chemical structure surrounding the gene cannot be explained by genetics or family environment. Our results suggest that victimization experiences are the source of these changes,” says Ouellet-Morin. According to the author, it would now be worthwhile to evaluate the possibility of reversing these psychological effects, in particular, through interventions at school and support for victims.
About this study
The study is published in Psychological Medicine under the title “Increased SERT DNA methylation is associated with bullying victimization and blunted cortisol response to stress in childhood: a longitudinal study of discordant MZ twins”:
Isabelle Ouellet-Morin is a researcher at the CSHS affiliated with the Centre de recherche Fernand-Seguin of the Hôpital Louis-H. Lafontaine. She is interested in the impact of victimization experiences on mental health and behavioural problems in adolescents and young adults, the underlying physiological and psychological mechanisms, and the factors that contribute to the vulnerability and resilience of individuals subjected to these experiences. She is also assistant professor at the School of Criminology at the Université de Montréal and researcher with the Research unit on children’s psychosocial inadaptation.
L’Hôpital Louis-H. Lafontaine – Institut universitaire en santé mentale
The Hôpital Louis-H. Lafontaine provides specialized and ultra-specialized services in mental health. As a leader in its field, the hospital develops knowledge through research, teaching, and assessment. The Hôpital Louis-H. Lafontaine is a member of the Université de Montréal excellence in health network. www.hlhl.qc.ca
The Centre de recherche Fernand-Seguin of the Hôpital Louis-H. Lafontaine
Affiliated with the Université de Montréal, the Centre de recherche Fernand-Seguin of the Hôpital Louis-H. Lafontaine and its partners, the Hôpital Rivière-des-Prairies and the Institut Philippe-Pinel de Montréal, is recognized by the Fonds de la recherche en santé du Québec. At the forefront of knowledge, it is one of the most important institutes for mental health research in French-speaking Canada. The CSHS is a centre of studies of the Centre de recherche Fernand-Seguin.
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