One in five of your friends, classmates or colleagues likely suffers from a mental illness.

Unfortunately, research has shown this to be the case, according to the National Survey on Drug Use and Health. Two of the most prevalent mental disorders are anxiety disorders and depression.

Anxiety disorders — the most common mental illness, according to the Anxiety and Depression Association of America — affect 18 percent of the U.S. adult population. Anxiety disorders include post-traumatic stress disorder, obsessive-compulsive disorder and certain phobias.

“It’s a combination of a lot of different things that lead to anxiety in college students,” said Stephanie Wonders, junior family social services major. “Academic stress and work and friendships and [not] getting enough sleep; it’s a combination of all of that stuff.”

Symptoms of depression include a dejected mood or diminished interest for two weeks or more. It’s not uncommon for someone with an anxiety disorder to also suffer from depression or vice versa, and the two often go hand-in-hand, according to the Anxiety and Depression Association of America.

If you suffer from depression or you know you are at risk, there are actions you can take that may help your mental state.

According to a study published in October and conducted by the Icahn School of Medicine at Mount Sinai, inflammation related to stress can increase your risk for depression. This calls for actions known to reduce inflammation and stress, such as a well-balanced, anti-inflammatory diet and consistent exercise.

Research published in September in the BMJ Open also indicates diet could play a major role in depression and other mental illnesses. Dr. Saverio Stranges, who headed this research, explained that the data suggested the “higher an individual’s fruit and vegetable intake, the lower the chance of their having low mental well-being,” according to a Sept. 24 Medical News Today article.

Of course, this inverse relationship isn’t infinite. But, the research stated individuals have a better chance for “high mental well-being” when five or more servings of fruits and vegetables are consumed daily.

Exercise has also been shown to help with depression, particularly through neurotransmitter regulation. As autumn rolls into winter, this becomes especially important.

A longitudinal study published in October by the European College of Neuropsychopharmacology revealed that seasonal affective disorder — a depressive illness spurred by autumn and winter seasons — is marked by decreased levels of the neurotransmitter serotonin. Exercise has been shown to decrease depression, possibly by increasing serotonin levels.

In addition to making lifestyle modifications to support mental health, sometimes seeking professional counseling is necessary.

“All students at Northern are eligible to receive free confidential services at the Counseling and Student Development Center,” said Brooke Ruxton, licensed clinical psychologist and executive director of Counseling and Student Development. “We provide individual and group therapy as well as offering same-day walk-in appointments for people who may be in crises or needing to access our services.

“It’s also OK to … recommend to a friend that they talk to somebody or get some professional help if a student is ever concerned about the safety of a friend.”

If you or someone you know is suffering from a mental illness, don’t be afraid to take action.