Michael Meaney, PhD, FRSC, CQ, CM

Deciphering The Dialog Between Nature And Nurture

Picture a playground full of the energy and glee of 5 year-olds at play. It’s an archetypal image of childhood happiness, yet we know that in as few as 1 to 3 years some of these same frolicking and carefree 5 year-olds will be robbed of their joy and confidence by disorders such as Attention Deficit Disorder and Social Anxiety. Heartbreakingly, many of these same children will turn to drugs and away from a productive and enjoyable adolescence and onto a path that leads to anxiety, depression and potentially even suicide.

This path is shaped by both the quality of early childhood experiences and genetic predispositions in a tangle of nurture and nature connections and begs some pretty obvious questions – which of the 5 year-olds on the playground are we talking about and what can we do to prevent such sad fates? 

“At the end of the day, this is really the one central problem that I am driven to solve,” says Dr. Michael Meany, a researcher at the Douglas Mental Health University Institute both the Director of the Program for the Study of Behaviour, Genes and Environment as well as James McGill Professor in the Departments of Psychiatry and Neurology and Neurosurgery at McGill. “How can we identify the children who are most at risk and put in place appropriate interventions at ages early enough to provide sustained benefits?”

Dr. Meaney, who also leads the Ludmer Centre, the world's first to integrate genomic, epigenetic, and mental health research as well as informatics, is perhaps ideally suited to provide answers to this complex question. Widely considered a giant in the field of epigenetics and mental health, he made headlines around the world in 2004 by being one of the first researchers to describe how maternal care influences gene expression in the offspring of rats.

“We began studies with animals looking how, even in adult rats or mice, maternal care affects the activity of genes in brain regions that regulate stress responses,” he explains. This maternal effect on gene expression involves epigenetic modifications that control the activity of genes. 

Epigenetic signals are simply chemical modifications to the DNA that regulate the expression, or activity, of genes.  Maternal care influences these epigenetic signals at genes that influence the nature of the stress responses. 

In 2009, Dr. Meaney and his colleagues applied these insights to human studies where they looked at samples of brain tissue from suicide victims who had been abused as children, suicide victims who had not been abused, and individuals who had not been abused and had died of natural causes.

In this groundbreaking research Dr. Meaney demonstrated for the first time with humans that early childhood experiences leave biochemical markers in an individual’s DNA. In other words, experiences in the family context, particularly during the first years of life, become part of a child's biology and influence the child's health and attainments throughout life – in positive as well as negative ways.

Dr. Meaney has since started to examine whether the epigenetic marks associated with childhood adversity might predict the risk for mental disorders, which would permit earlier intervention or prevention, and the response of individuals with mental disorders to treatment. 

“Now that we know that childhood experiences change how genes are expressed, we may be able to identify the children who are most at risk and develop therapies tailored to the needs of each child,” he says.

"Our biggest challenge now is to understand the biology of vulnerability, the risk an individual carries," explains Dr. Meaney. “Second, can we then chart the reversibility through intervention programs? And can we evaluate the biological impact of the intervention at the level of the individual?"

Dr. Meaney has published preliminary studies that support both ideas.  For example, he has found that the epigenetic signals on the ‘stress response’ genes predicts post-traumatic stress disorder symptoms among American war veterans and also predicts their response to treatment. 

“The major challenge is really to put this knowledge to work in meeting the objective of prevention,” he says.

 

Dr. Meaney was selected as the 2014 Klaus J. Jacobs Research Prize Laureate in recognition of this pioneering, cutting edge research on the biological mechanisms by which parental behaviour affects brain development and lifelong function. Among other achievements, he was named a "Most Highly Cited Scientist" in the area of neuroscience by the Institute for Scientific Information in 2007 and was also elected to the Royal Society of Canada (RSC) and named a Knight of the National Order of Quebec.  For research on stress Dr. Meaney has received a Senior Scientist Career Award from the Canadian Institutes of Health Research (CIHR) and, along with fellow researcher from the Douglas Institute Dr. Gustavo Turecki, was awarded the Scientist of the Year Award by Radio-Canada. In 2011, he was made a Member of the Order of Canada.