Growing brains, shifting environment affect mental health

Psychologists say many are diagnosed between ages 18 and 25, a phenomenon tied to vulnerabilities in brain development and environmental changes.

Photo from iStock Photo from iStock

By Heather Mongilio/Matters of the Mind

Ben Saunders, 21, was starting his junior year at Georgetown University last year when he noticed his functioning was off. He had spent the previous semester studying abroad in Japan where he was using Japanese every day. But back in his Japanese class at Georgetown, he couldn’t put a sentence together.

“And that was kind of scary,” Saunders said.

‘My brain [was] just not working […] And it’s a terrifying thing to lose your brain.’


Saunders said he was also forgetting things and feeling down. His mood was “fluctuating between down and empty to maybe okay,” he said. He had recently gone through a breakup and thought it was responsible for his down mood.

A good student, Saunders figured out how bad his dysfunction was when his schoolwork became a challenge. He was writing an essay and had planned to pull an all-nighter to work on it. He started at 8 p.m., but by 6 a.m. he had only one page finished.

“My brain [was] just not working,” Saunders, now a senior studying international economics at Georgetown University, said. “And it’s a terrifying thing to lose your brain.”

Saunders went to the Counseling and Psychiatric Services (CAPS) office at Georgetown where he said he was ultimately diagnosed with depression at age 19.

A common age for a mental health diagnosis

The timing of Saunders diagnosis is not unusual. Being diagnosed with a mental illness is common around college age, according to psychologists.

Mental disorders often appear around ages 18-25, according to Erika Forbes, Ph.D., associate professor of Psychiatry, Psychology and Pediatrics at the University of Pittsburgh Medical Center.

She said most disorders, such as depression, bipolar disorder and schizophrenia, will have developed between ages 18-20. Substance abuse commonly starts in the late teenage years and early 20s, while eating disorders tend to appear during the teenage years.

Mood disorders such as depression are also known to start emerging during this age period, as described via e-mail by Monique Ernst, Ph.D., head of Neurodevelopment of Reward Systems at the National Institutes of Health.

But while it is know that disorders emerge during this time, the reason why is still “the question of the day,” Ernst said.

A change of scene and a loss of support

It is likely that the interaction between the environment and brain development is responsible for the emergence of mental illnesses, according to Ernst.

Many young adults leave their homes at 18 to go to college. In this new environment, they lose their network of family and friends established in childhood and adolescence. The loss of that support system can be damaging, which is why mental illnesses may begin to appear during college, Ernst said.

“There’s a really big change going on when you go to college,” she said.

Social changes, such as the ending of a relationship, can add stress for people who are already vulnerable, Forbes said.

Saunders had just ended a relationship when he began to notice changes in his ability to function; while this may have affected his mental health, he said he does not know if it was the trigger.

‘I told [my friend] I didn’t know if I was crazy or if I had hit rock bottom.’“Depression doesn’t wait for reasons,” Saunders said. “It just occurs.”


But college also is a time of change in another area — the brain.

“It is a vulnerable time for a lot of reasons,” Forbes said.

One of the reasons that mental disorders often develop between ages 18-25 is that there are vulnerabilities in brain development, Forbes said. The brain does not finish development until age 25, especially in the frontal lobe, she said. The frontal lobe is central to human personality and communication skills. Abnormalities in that area have been connected with both depression and schizophrenia.

The connections between different parts of the brain are also vulnerable to dysfunctional development during these ages.

“Mental health problems are brain disorders,” Forbes said.

But there are no specific markers psychologists can look for in the brain when it comes to development of disorders because each person’s brain is different, Ernst said.

In depression, one structural change that occurs is in the hippocampus, a structure in the brain responsible for memory consolidation and learning. The hippocampus, which is full of receptors for chemicals released during stress, is noticeably smaller in people who are diagnosed with depression, she said.

The hippocampus is full of stress chemical receptors, so the increase of the stress hormone in the system flushes the hippocampus. This causes damage to the hippocampus that can result in physical shrinking and memory dysfunction. But the question is whether people develop depression as a result of stress shrinking the hippocampus, or if people have smaller hippocampi because they have depression.

A doctor never examined Saunders’ hippocampus, but it is possible his memory loss was tied to structural changes. Saunders said his memory loss was one of the scarier and more frustrating aspects of his depression.

“I told [my friend] I didn’t know if I was crazy or if I had hit rock bottom,” Saunders said.

Saunders started therapy and medication following his diagnosis, but it didn’t help the memory problems immediately, he said. Other ups and downs followed.

He was studying for an economics exam and was having trouble recalling information he knew the previous day.

“Things that came easily to me just weren’t there,” he said.

Saunders is not currently under treatment by a professional for depression, but said he is managing his condition with meditation, taking vitamins and mindfulness exercises like journaling.

Finding the roots of depression earlier

While mental illness typically emerges between ages 18-25, recent research suggests that the traits that lead to increased risk for mental illness are developing earlier.

Judith Morgan, Ph.D., assistant professor of psychiatry at University of Pittsburgh Medical Center, is currently conducting research looking into the development of disorders at younger ages. Forbes wrote in an e-mail that the research has shown interesting results already.

There are some traits that develop during childhood that place the individual at risk for the development of a mental illness during adolescence, Morgan wrote.

Morgan looks at children who are at risk for the development of depression because of family environment to see how they experience positive and rewarding events compared to children who are not at risk.

Her research is ongoing, but initial data shows that children at risk for depression react less positively than other children when presented with rewarding stimuli, like a prize or someone smiling at them, she wrote.

Positive emotion can act as a buffer against stress, which can affect the severity of depression, Morgan wrote.

“These early differences may be associated with greater vulnerability to later clinical disorder, such as depression during adolescence, because positive emotions can help buffer against stress and promote resilience,” Morgan wrote.

Saunders said he does not recall being sad as a child, but he was not particularly happy either.

While development of the disorders may start earlier than expected, the interviewed psychologists all agreed that adolescence is a vulnerable time for mental illnesses such as depression or anxiety to appear.

A ‘risky’ time for adolescents

Adolescence is a time of risk taking, Ernst said. The brain is adapting to changes in environment and behavior that cause it to strengthen certain circuits and cut others.

Genetics may also play a role, she said.

Because of these changes, adolescents can begin to plan goals in ways they could not as children. But if the goals fail, the feelings of disappointment can lead some to be more vulnerable for development of depression, Morgan said in an e-mail.

‘You have to know [that developing a mental illness] is not your fault’


“Some youth are better able to bounce back from these disappointments, and a natural tendency toward high positive emotion expression may help youth cope with this loss,” she said in the e-mail. “In contrast, youth who are naturally less positive and exuberant, and have been since early childhood, may be at increased risk for developing depression, because they may not have the benefit of positive emotions to buffer against these negative feelings and motivate them to keep trying in the face of loss.”

This may have been the case with Saunders and his recently-ended relationship. But Saunders said that this particular life event made him confront issues that, in retrospect, may have been present all along.

“I was never comfortable being happy,” he said.

Unlike the psychologists who study depression for a living, Saunders is not concerned about what triggered his depression. Instead he focuses on moving forward with his life.

“You have to know [that developing a mental illness] is not your fault,” Saunders said.

Matters of the Mind on Twitter