Dr. Marisa Silveri detailed research that shows the ways in which brain development during adolescence can be stunted by drug and alcohol use to Roxbury Latin parents at the school Thursday night.

According to Silveri, a psychiatry professor at Harvard University whose research comes out of McLean Hospital, the teenage brain - particularly the frontal lobe - is undergoing such wide-sweeping changes that the use of drugs and alcohol can have an effect on adolescents' ability to use logic in making decisions.

"Teens don't have the frontal lobe working quite as well as adults," Silveri said. "It makes the teen brain a lot more vulnerable."

The frontal lobe is responsible for what Silveri called the brain's "executive functions," such as planning, organizing, memory, and decision-making. During adolescence, research shows that the whole brain, but the frontal lobe especially, undergoes an intense remodeling process to enhance communication between brain cells.

But images collected from MRIs suggest that the effects of drugs and alcohol consumption require the brain to exert far more energy in the frontal lobe during adolescence.

"We actually see that the brain is far less efficient," Silveri said.

Over the course of her presentation, Silveri provided images and data showing that teens who drink regularly (meaning, she said, on weekends) perform 10 percent worse on memory tests.

"The brain is busy dealing with alcohol being on board," she said. "It changes what it's doing."

Silveri suggested that parents explicitly tell their teens that their brains are not fully developed, thereby heightening their awareness that they may not be ready to make good decisions in social environments. She suggested employing a "10-10-10" strategy, under which a student is essentially forced to take more time and exert more energy to make a decision about whether or not to succumb to peer pressure situations.

"Ask, 'Are you going to make the same decision 10 seconds later? Ten minutes later? How about 10 days later?'" she said.

RL Dean of Students Paul Sugg was pleased to see that a high number of parents turned out for the event.

"The attendance is heartening," he said. "It suggests we all have interest in this issue."

Silveri's research also revealed the following:

• Teens who start drinking before the age of 13 stand a 40 percent chance of developing a substance abuse problem. The odds for teens who wait until they turn 18, by contrast, stand at only 20 percent, and for those who wait until the legal age of 21, the number is down to 10 percent.
• Teens who use marijuana exhibit brain activity when the brain is supposed to be at rest but lack activity when asked to do something.
• Amongst marijuana-using teenagers, the ability to prevent themselves from providing the wrong answer or decision to a given prompt requires far more frontal lobe activity than a non-user.
• Teens with a family history of substance abuse, even if they have not started using drugs or alcohol, have exhibited heightened frontal lobe activity.
• Because it can have an effect on students' sleeping patterns, caffeine can also be said to have an effect on frontal lobe activity. Sleep and a healthy diet, alongside drug and alcohol consumption, have an effect of frontal lobe development, so if students are sleeping less because they are drinking coffee, they can suffer similar consequences.