An important stage in brain development in teens hits just as many individual move away from home to college -- which has more mental health ramifications than students may know.

"The stage at which the brain is developing -- it actually puts young people at risk for certain behaviors," said Dr. Donald Vereen, director of the University of Michigan's Substance Abuse Research Center. "The part of the brain that reasons -- the frontal lobe -- is the last to form. In late adolescence, the frontal lobes are not finished forming; there are still connections that need to be made, and kids are put in some of the most stressful situations in their lives."

"They move away from home. They have to study and make good grades. They're starting to work. They have to interact with people whose brains didn't develop so well -- and negotiate life with them. It's a wonder that all kids aren't depressed, if you think about it."

Vereen was the keynote speaker on the first day of the University of Michigan's 11th Depression on College Campuses conference Tuesday in Ann Arbor.

About 15 percent of students surveyed recently at the University of Michigan say they're struggling with depression -- a figure that's on par with campuses across the country.

Brains are depressed, not people, Vereen said.

The brain is the organ with the disease, not the person, Vereen said. Depressed brains have less blood flow or glucose than non-depressed brains.

The brain cells of newborn babies have limited connections. As the baby’s brain develops over the first two years of life, the cells grow and increasingly become interconnected as the child learns about the world around them, Vereen said.

“Soon, you have an organized organ,” Vereen said.

With children, brain development is directly correlated with their behavior. Young children that seem to be “everywhere” and easily distracted have brains that rapidly are growing and learning, Vereen said, calling them a "hot, molten volcano" of activity.

Between the ages of 14 and 18, however, brain development changes. Brain cells “prune” themselves according to an individual’s experience - leaving behind the cells that define a person, Vereen said.

The age range also is when depression first develops, Vereen said.

A teenager’s brain negotiates inner selfish needs and wants as it selects from necessary and unnecessary cells, while it also manages outward stimuli, Vereen said.

When a brain can’t negotiate between what’s happening in its immediate environment and the process happening internally, there’s a struggle in the brain, Vereen said.

The inability to deal with those emotions and to calm oneself often leads teenagers to self medicate -- because they’re both curious and testing their boundaries, and because they want to feel better, Vereen said.

“If they’re boys, they don’t sit well with feelings,” Vereen said. “They have to do something to make themselves feel better, and so they often get in trouble.”

Teens often turn to drugs and alcohol to self-medicate.

"There are tremendous stressors in the process that really make young people vulnerable to things like accidents, driving fast in the car, pregnancies and the inability to not soothe oneself -- and it is hard, it is difficult -- might lead to unwise choices. Like trying drugs; trying to fix or re-write, re-correct the brain," Vereen said.

“Drugs take advantage of unformed brains,” Vereen said.

A recent survey of 23,000 individuals between the ages of 11 and 20 years old found that more of them say they have trouble managing anger and report depression issues than use drugs and alcohol illicitly or have unprotected sex.

The survey was conducted under the direction of Dr. Jennifer Salerno, who is the founder of Possibilities for Change.

The organization is a part of the University of Michigan Tech Transfer Venture Acclerator, and developed the Rapid Assessment for Adolescent Preventive Services survey.

About 28 percent of those surveyed reported having trouble managing anger, and 24 percent reported signs of depression.

However, 14 percent of respondents reported using illicit drugs and alcohol, and 13 percent said they’ve had unprotected sex.

The survey was given to 23,000 students in medical practices and school-based health centers across the country using an online form. The 21-question health risk assessment tool took about five minutes to complete.

“With so much attention being paid to the usual suspects of drugs, alcohol, pregnancy and STD prevention, these much more common risks are being overlooked,” Salerno said in a statement. “The real value of a standardized approach to risk assessment with teens is the ability to uncover these hidden dangers that they aren’t likely to bring up - and we, as adults, might not even think to ask.”

Amy Biolchini covers Washtenaw County, health and environmental issues for AnnArbor.com. Reach her at (734) 623-2552, amybiolchini@annarbor.com or on Twitter.