While not all impulsive behavior is indicative of mental illness, a variety of mental health disorders common in adolescence, including depression and substance abuse, have been linked to impulsivity. Therefore, finding a way to identify and treat those who may be particularly prone to impulsivity early in life is especially important.
A group of researchers led by McGill University scientists have developed a genetic-based score that could help identify, with a high degree of accuracy (greater than any impulsivity scores currently in use), young children most at risk of impulsive behavior .
Their results are particularly compelling because the score they developed was able to identify those at higher risk for impulsivity within three ethnically diverse community samples of children from a cohort of nearly 6,000 children.
This discovery of a novel early-life score for impulsivity may inform prevention strategies and programs for children and adolescents at risk for psychiatric disorders. In addition, by describing the function of the gene networks that make up the score, the study may stimulate the development of new therapies in the future.
A change of perspective leads to new insights
The Impulsivity Risk Score was developed by examining the co-expression of a number of genes in the prefrontal cortex and striatum, areas of the brain that play a role in decision-making and emotion regulation, among other things.
“Typically, genetic approaches to identifying the neurobiological signature for impulsivity (or any other condition or disease) focus on identifying the variation of some genetic markers that might be responsible for the problem,” said Patricia Pelufo Silveira, associate professor in of the Department of Psychiatry and a researcher at the Douglas Research Center and one of the two senior authors of the recent publication in Molecular Psychiatry. “We approached the problem from the opposite direction, focusing on a gene known to be associated with brain maturation in these two key areas, and then looking for a network of other genes that are most closely related were associated with it.”
It hunted a lot
This approach was based on previous work in mouse models led by Cecilia Flores, co-senior author of the article and full professor in the Department of Psychiatry, which identified the importance of a particular gene (known as DCC), which acts as a “guidance cue” that determines when and where exactly the brain’s dopamine cells make connections in the prefrontal cortex and striatum. This coordinated development is essential for the maturation of impulse control.
But creating the new impulsivity score required a lot of hunting to narrow down the genes most closely linked to them DCC. “Our approach exploits the fact that genes operate in complex networks that ultimately perform very precise biological functions. These so-called gene networks have the property of being very tissue-specific, so we started with an unbiased look at groups of genes co-expressed with DCC in brain regions known to play important roles in supporting inhibitory control,” says co-author Jose Maria Restrepo, a graduate student in the Integrated Program in Neuroscience at McGill University.
“The results underline the importance of data sharing and open science,” adds Flores. “Imagine if we had to collect this information in all these countries over the years. Our discovery was only possible because we had access to all of this data.”
About McGill University
Founded in 1821 in Montreal, Quebec, McGill University is Canada’s premier medical doctoral university. McGill is consistently ranked as one of the top universities both nationally and internationally. It is a globally recognized higher education institution with research activities spread across three campuses, 11 faculties, 13 professional schools, 300 degree programs and over 39,000 students, including more than 10,400 doctoral students. McGill attracts students from over 150 countries around the world, its 12,000 international students make up 30% of the student body. Over half of McGill students report having a first language other than English, including approximately 20% of our students who say French is their first language.