Researchers have discovered a genetic key that could one day help treat mental illnesses associated with parts of the brain used for decision making, impulse control, and other higher mental functions.
This brain area, known as the prefrontal cortex, plays a role in several psychiatric disorders whose symptoms first appear during the teenage years. It continues to develop well into early adulthood.
“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," Cecilia Flores, Ph.D., senior study author and an associate professor in the McGill University department of psychiatry, said in a press release. "Prefrontal cortex wiring continues to develop into early adulthood, although the mechanisms were, until now, entirely unknown.”
'Teen Gene' Involved in Mental Illnesses
Throughout adolescence, connections between the brain cells in this region continue to mature, a process that involves the so-called ‘teen’ gene. In the new study, published today in Translational Psychiatry, researchers found that this gene may play a role in determining how vulnerable a person is to schizophrenia, depression, drug abuse, and other mental illnesses that involve the prefrontal cortex.
“The prefrontal cortex is significant in determining executive functioning—decision making, cognitive reasoning, and so forth,” says Rick Meeves, Ph.D., LMFT, Director of Adolescent Clinical Services at the CRC Health Group, who was not affiliated with the study. “Those become pretty severely impaired in the cases of schizophrenia or other severe mental health disorders.”
The researchers found that mice with a dysfunctional copy of the 'teen gene,' formally known as DCC, did in fact show signs of behavioral problems that extended into adulthood.
“We looked at behaviors in mice that are similar to some behaviors that are observed in humans who suffer from certain psychiatric illnesses,” says Flores in an email to Healthline.
Moreover, the researchers found that the DCC gene was more active in the brains of people who had committed suicide than in those of healthy people. The researchers believe that toning down the gene's action may provide some level of protection against psychiatric disorders involving the prefrontal cortex.
Discovery Could Unlock New Treatments
While the researchers' work focused on mice, the study offers a first glimpse of how genetics can affect this area of the brain.
“They’re identifying not just the gene that controls development of the prefrontal cortex,” says Meeves, “but also what intervention of chemicals might assist in the development of the connections so that it gets fully developed.”
In addition to the potential for new drug treatments to treat schizophrenia and other mental illnesses, the research may also provide doctors with clues as to which teenagers are most at risk of developing schizophrenia, substance abuse, or depression.
“If they can unlock this, it will be a significant discovery,” says Meeves, “because there haven’t been any great answers, pharmacologically or biomedically, in being able to determine this.”
Flores and her team are continuing their exploration of DCC in mice, but with an eye toward other factors that can affect the gene's expression.
“One of the things we are studying now is how exposure to factors that are known to increase the risk for certain psychiatric disorders—for example drugs of abuse during adolescence—alter the expression of the DCC gene and then in turn alter the development of the brain,” says Flores.
“We are also investigating whether ‘positive’ events—for example, breeding mice in an ‘interesting’ and ‘rich’ environment also modify DCC,” she adds.
Treatments Aim to Stimulate Brain Development
While still several years away, new treatments based on this work will likely involve a combination of drugs and therapies designed to affect the development of the prefrontal cortex.
“The prefrontal cortex is also an area responsible for human interaction, which is called Theory of Mind,” says Joseph Shrand, M.D., a psychiatry instructor at Harvard Medical School, and author of Outsmarting Anger. “This is our basic ability to appreciate what somebody else is thinking or feeling—it’s empathy.”
In his work with teenagers, Shrand uses an approach based on the Theory of Mind to direct thinking from the brain’s emotional and impulsive limbic system—the part of the brain that often predominates in teenagers—to the prefrontal cortex.
This method, which is relevant for people of all ages, emphasizes accepting a person’s behavior as the best that he or she can do at that moment, without condoning it or judging it. In that way, anger and anxiety can be diffused.
“By using respect, we can modify emotion and shift a person to their prefrontal cortex,” he says, “so they can begin... looking at why they do what they do, and anticipating the consequence.”