A new understanding of the neurobiology of impulsivity

While not all impulsive behavior is indicative of mental illness, impulsivity has been associated to a variety of mental health conditions, including depression and substance misuse, which frequently manifest in adolescence. Therefore, it's crucial to develop a means to spot and treat those who could be particularly prone to impulsivity at a young age.

Researchers at McGill University have developed a genetic score that could be used to identify young children who are most at risk of impulsive behavior with a high degree of accuracy (higher than any impulsivity assessments now in use).

Their results are particularly intriguing because the score they established allowed them to identify children from three ethnically diverse community samples who were at a higher risk of impulsivity from a cohort of almost 6,000 kids.

The identification of a new score for impulsivity in childhood can help with prevention plans and initiatives for kids and teenagers who are at risk for mental health issues. The study can also encourage the creation of novel treatments in the future by defining the function of the gene networks that make up the score.

The co-expression of many genes in the prefrontal cortex and the striatum, regions of the brain involved in decision-making and emotional control, among other things, was examined to create the impulsivity risk score.

According to Patricia Pelufo Silveira, Associate Professor in the Department of Psychiatry and Researcher at the Douglas Research Centre, one of the two senior authors on the recent paper in Molecular Psychiatry, "Traditionally, genetic approaches to identifying the neurobiological signature for impulsivity (or any other condition or disease) tend to focus on identifying the variation in a few genetic markers that might be responsible for the problem." "We approached the issue from the opposite side, first focusing on a gene known to be related to the maturation of the brain in these two crucial locations and then searched for a network of other genes that were most closely associated with it," said Dr. Wang.

Earlier research in mice models, led by Cecilia Flores, a co-senior author on the paper and a Full Professor in the Department of Psychiatry, established the significance of a particular gene (known as DCC), which serves as a "guidance cue" that determines when and precisely where brain dopamine cells form connections in the prefrontal cortex and striatum. This strategy was based on these findings. The growth of impulse control depends on this synchronized development.

However, it took a lot of searching to identify the genes most closely related to DCC in order to produce the new impulsivity score. "Our method takes advantage of the fact that genes function inside intricate networks that, in the end, carry out extremely specific biological roles. We started by taking an objective look at groups of genes that are co-expressed with DCC in brain regions known to play a significant role in supporting inhibitory control because these so-called gene networks have the property of being highly tissue-specific "says co-author Jose Maria Restrepo, a PhD candidate in McGill University's Integrated Program in Neuroscience.

According to Flores, the findings "underline the importance of data sharing and open science." "Imagine if we had to gather this data over all of these years in all of these nations. We could only have made our finding if we had had access to all of these data."

McGill University