The link between creativity and mental illness has been a fascinating topic for many researchers.

For example, well-known author Kurt Vonnegut was intermittently depressed, but that was only the beginning. His mother had suffered from depression and committed suicide on Mother's Day when Kurt was 21 and home on military leave during World War II. His son, Mark, was originally diagnosed with schizophrenia and later, bipolar disorder.

While mental illness seems to run rampant in the Vonnegut family, so does creativity. Kurt's father was a gifted architect, and his older brother Bernard was a talented physical chemist and inventor who accumulated 28 patents. Mark is a writer, and both of Kurt's daughters are visual artists.

A few well-known creative people who ended up losing their battles with mental illness through suicide include Virginia Woolf, Ernest Hemingway, Vincent van Gogh, Kurt Cobain and recently Robin Williams.

Is there a connection between creativity and mental illness? If so, what is it, and can that connection be used to treat mental illness?

Using a well-validated test of creativity, a UNC School of Medicine study has provided the first direct evidence that a low dose of electric current can enhance a specific brain pattern to boost creativity by an average of 7.4 percent in healthy adults. A 10-Hertz current was run through electrodes attached to the scalp, which enhanced the brain's natural alpha wave oscillations — prominent rhythmic patterns that can be seen on an electroencephalogram (EEG).

According to senior author, Flavio Frohlich, Ph.D., this research called the Cortex study is the first evidence that specifically enhancing alpha oscillations are a causal trigger of a specific and complex behavior, such as creativity.

Frohlich's team enrolled 20 healthy adults and placed electrodes on each side of each participant's frontal scalp and a third electrode toward the back of their scalps. This way, the 10-Hertz alpha oscillation stimulation for each side of the cortex would be in unison. This is a key difference in Frohlich's method as compared to other brain stimulation techniques.

Each participant underwent two sessions. During one session, researchers used a 10-Hertz sham stimulation for just five minutes. Participants felt a little tingle at the start of the five minutes. For the next 25 minutes, each participant continued to take the Torrance Test of Creative Thinking, a comprehensive and commonly used test of creativity. In one task, each participant was shown a small fraction of an illustration as a bent line on a piece of paper. Participants used the line to complete an illustration, and they wrote a title when they finished.

In the other session, each participant underwent the same protocol except they were stimulated at 10 Hertz for the entire 30 minutes while doing the Torrance test. The tingling sensation only occurred at the start of the stimulation, ensuring that each participant did not know which session was the control session.

Because rating creativity or scoring a test can involve subjectivity, Frohlich sent each participant's work to the company that created the test. The company was only asked to score the test and was not told anything about the study.

When Frohlich's team compared each participant's creativity score for each session, they noted that during the 30-minute stimulation sessions, participants scored an average 7.4 percentage points higher than they did during the control sessions. In fact, several participants showed incredible improvements in creativity.

What's the link to mental illness? Evidence strongly suggests that people with depression have impaired alpha oscillations. If these brain activity patterns can be enhanced, then, hopefully, many people could be helped. Frohlich hopes to use this approach to help people with neurological and psychiatric illnesses.

Frohlich, who is a member of the UNC Neuroscience Center, is now in collaboration with David Rubinow, M.D., chair of the department of psychiatry, to use this particular kind of brain stimulation in two clinical trials for people with major depressive disorder and premenstrual dysphoric disorder. Patients are currently being enrolled in both trials.