Take any intro-level improv class, and on day one, when everyone is sharing why they're there, you'll likely hear a few say "to build " or "reduce ." I've encountered this many times in my years in improv, but didn't quite understand why this particular art form seemed so beneficial to the socially . So I decided to investigate.

What I found was simple, but powerful.

Defined as the of interacting with other people, social anxiety is usually caused by panic at the idea of being negatively judged or scrutinized. Though some with social anxiety may fare well socially, they’re often internally freaking out. This can present physical symptoms, such as a fast heartbeat or dizziness, according to the Anxiety and Depression Association of America.

When social anxiety is strong or debilitating, it’s referred to as . This is not just occasional and slight anxiety before a speech. People with this disorder may worry for weeks before that speech, if they even show up, according to the National Institute of Mental Health (NIMH). Social anxiety disorder affects around 15 million Americans, or 6.8 percent of the population. Both social anxiety and social anxiety disorder are often treated with anti-anxiety medications and/or .

Source: Steve Rogers Photography, used with permission.

Some are also treated with improv, a form of theatre where everything said and done is made up on the spot. Whether it’s one long, improvised narrative or a quick game of “Questions only” (where players in the scene can only ask questions), the main “rule” of improv is known as the “yes, and” principle. According to improv teacher David Alger on the Pan Theater website, “For a story to be built…the players have to agree to the basic situation and set-up.” Agreement is the “yes.” Adding new dialogue, actions, or objectives is the “and.” Performers know that whatever they say will be accepted by other players in the scene. That’s why improv can be so helpful for social anxiety, which often stems from a fear that the opposite will happen (rejection). Failure is so de-emphasized in improv that some intro-level improv classes even include what's known as the "failure bow," where a student, after perceiving he/she failed in a scene, bows and yells out "I failed!" as other students cheer aloud.

Enough activities like that can change the brain, according to Mark Pfeffer, a therapist in Chicago and the director of Panic Anxiety Recovery Center (PARC).

“It helps us realize that it’s okay to say something silly or stupid,” Pfeffer said.

Since 2011, Second City Theater in Chicago has offered classes, in conjunction with PARC, titled “Improv for Anxiety.” Pfeffer helped start these eight-week classes, which are designed to help people fight social anxiety through a combination of regular improv activities (taught by improv teachers) and cognitive behavioral therapy ( ) support groups (run by licensed therapists). The CBT portion works on altering patterns to change the way someone feels. There’s lots of evidence of CBT working, but only anecdotal evidence on the effectiveness of improv on social anxiety. The first academic study on the topic will be published later this year by the University of Chicago, in conjunction with Second City and PARC.

Social skills coach Daniel Wendler commends Second City for including CBT in that class. Even though he uses improv games to help his socially anxious clients, he doesn’t think improv should be treated as a substitute for therapy.

“If you have a severe case of social anxiety disorder or anxiety coming from past , that’s something in the realm of a mental health professional,” said Wendler, who is based in Portland, Ore., and the author of Improve Your Social Skills. “You shouldn’t just say, ‘Go to improv for a month and you’ll be cured.’”

According to Pfeffer, doing just one or the other (improv or therapy) has proven not to work as well as doing both.

“The combination is magic,” Pfeffer said.

In the “Improv for Anxiety” classes, some with more severe social anxiety drop out, thinking they can’t do it, or that they need more therapy sessions first. But then there are people like a client of Pfeffer’s, who was on the verge of dropping out of college, because he feared being around people in class. When he was overwhelmed, he’d often pretend to get a call and flee the room, sometimes in such a hurry that he left his possessions behind. After taking the classes at Second City, however, he learned to control his anxiety and now works in a managerial role at a nonprofit organization. Stories like that have led Pfeffer to believe that people of all social-anxiety levels can potentially benefit from improv when it’s coupled with therapy.

Jessica Arjet, co-owner of the Hideout Theatre in Austin, Texas, has seen similar results.

“When people gain the experience of making lots of mistakes where the consequences are positive rather than negative, they start to accept risk and embrace it,” said Arjet, who teaches improv classes to adults and improv classes to kids and teens with Asperger syndrome.

Arjet told me about one of her students, who was incredibly shy and scared of being around people when he began classes at age 13. In the first semester of class, he only participated in exercises that didn’t require talking. By his second semester, he was participating in all types of games. Over those two years, he also went from playing music alone (a hobby of his) to performing shows in front of an audience. Arjet attributes much of that transformation to improv.

And it’s not hard to see why. Improv makes failure seem safe, which is exactly what’s needed for the socially anxious.