Parents of mentally ill adults have long reported that the first signs of mental illness emerged during their children’s teen years. Now researchers say they’ve identified what they call the “teen gene,” which could be the biological trigger for teen-related behavioural problems.

Researchers at the McGill-affiliated Douglas Institute Research Centre say the gene, called DCC, controls dopamine connectivity in the prefrontal cortex during adolescence, and that dysfunction of the gene -- through stress and drug abuse, for example -- can lead to long-term mental health consequences.

The prefrontal cortex, associated with judgment, decision-making and flexibility, is crucial for learning, motivation, and cognitive processes. And because the prefrontal cortex continues to develop into adulthood, the region is highly susceptible to being shaped by life experiences in adolescence.

"Certain psychiatric disorders can be related to alterations in the function of the prefrontal cortex and to changes in the activity of the brain chemical dopamine," said Cecilia Flores, senior author on the study and psychiatry professor at McGill University. "Prefrontal cortex wiring continues to develop into early adulthood, although the mechanisms were, until now, entirely unknown."

The breakthrough discovery, which provides the first clues to a fuller understanding of brain development, could hold promise in combating severe mental illness, the researchers say.

“What we are finding is that the function and the amount of DCC that we have during adolescence can determine our vulnerability to certain psychiatric disorders in adulthood,” Flores told CTV News.

And what’s more, the study suggested that “the amount or the levels of the DCC gene during adolescence can be changed (through) life events.”

Dr. Hazen Gandy, a child and adolescent psychiatrist at CHEO,notes the work was partially done in mice,which means much more work needs to be done to confirm it plays a role in humans.

“It is a piece of the puzzle;I think it’s hard to say how big a piece it is-- we have to appreciate that this is research in animal models and we always have to be careful about translating what we find in animal models in terms of how that really translates in human behaviour,” Gandy told CTV News. “But it is a piece of larger puzzle of understanding human brain development, and I think it speaks to the need for us to really look at focusing on early detection and working on better ways of intervention in the adolescent population.”

And psychiatrists agree that early therapy and support for adolescents who display mental health issues can lead to a healthy adulthood.

Ridha Joober, a psychiatrist at Douglas Institute, said the study questions “are very interesting to ask because they basically give us a hint on what we were observing clinically.”

“They have shown in this paper that if you have some intervention, you can actually correct the brain abnormalities,” he told CTV News.

And the research underscores the need to treat teens showing symptoms of mental illness as soon possible, added Joober.

“It is important to intervene very early… to correct and to help young people who are suffering from mental disorders.”

With a report from CTV's medical specialist Avis Favaro