There are thousands of known and studied phobias from aulophobia, a fear of flutes; to xanthophobia, a fear of the color yellow.
"We had somebody who was deathly afraid of people hiccupping," said Dr. David Barlow of the Center for Anxiety and Related Disorders at Boston University. "They would not put themselves in a situation where they might be around someone who would be likely to hiccup."
If a person knows what their fear is, they know how to avoid it. But for more than six million Americans with panic disorder, they can never be sure what will spark their fear or when it will come over them.
Lindsay Lanouette is the last person you'd think has any reason for fear or worry. The 16-year-old from Falmouth, Maine, is a great athlete, gets good grades and has many friends.
"Sometimes I have the fear of like -- that I'm gonna like die," she said. "I guess, like, cause, I won't be able to get help."
But her panic attacks can set in at any time. You can see it happening in English class when her legs begin to shake uncontrollably.
"I'm always, like, constantly moving my legs," Lindsay said. "I don't even know if it's like a nervous habit."
Her panic might arise during gym class, when her heart started beating faster.
"My heart kind of starts racing a little bit, I just get really nervous," she said.
Outside the familiar confines of school, her symptoms are even worse.
"When I go to the mall by myself, generally, it's like I get kind of dizzy," Lindsay said.
Lindsay's parents say she's been struggling with panic her entire life.
"Initially, it was just some separation problems with going to daycare or kindergarten," said Kathy Lanouette, Lindsay's mother.
"She'll say that her hands are tingly, her feet are tingly, she feels separated from her body," said Jason Lanouette, Lindsay's father.
Up until now, the family has tried to cope by keeping Lindsay out of places where she panics, like restaurants and movie theatres. But they can't protect her forever. She's almost old enough to go to college.
"I just worry about -- sometimes because I think sometimes she feels really bad that she has this and doesn't understand it," said Kathy Lanouette. "I just worry about some of the thoughts that she has said before -- you know, that she … doesn't want to live anymore."
Recently, the family received new hope. A friend told the Lanouettes about the Center for Anxiety and Related Disorders, located two hours away at Boston University. The center offers a five-day intensive treatment program for adolescents like Lindsay. Dr. Donna Pincus helped lead her through it.
"I'd like you to just almost be like a scientist with me," Pincus told Lindsay. "I want us to watch what happens and I want us to watch what happens right before you have a panic attack."
Doctors are still studying what causes panic disorder. One theory is that it has to do with the amygdala, the part of the brain that coordinates the body's automatic response to fear. Perhaps it activates too frequently in certain people.
"What we have to do together is teach that watchdog in your brain to not bark so much at times when there's not really any danger there," Pincus told Lindsay during one of their sessions.
Pincus and other doctors at the center placed Lindsay in the very situations that cause her the most panic.
Days one and two of Lindsay's five-day treatment are devoted to psychotherapy. Pincus wants to train her not to run for help when her panic attacks set in.
"The more you avoid and decide, 'Okay, I'm not gonna stay at school and I'm not gonna stay in my bed at night,' what do you think happens to your panic thoughts?" Pincus said to Lindsay during one of their sessions. "The next time you get into your bed at night, do you think it will be easier or harder?"
"Harder," Lindsay said.
"Yeah, and do you think those panic thoughts might be even stronger," Pincus said.
"Yeah," Lindsay said.
Pincus told Lindsay that she needs to experience her feelings of anxiety in order to overcome them. She puts Lindsay through a series of exercises designed to produce the physical sensations that normally accompany her panic attack: Jogging in place to make her heart race; breathing through a cocktail straw to make her feel faint; staring at a bright light bulb, which makes her leg start to shake uncontrollably.
"Our goal is going to be is to continue to experience these feelings and allow the body to resolve itself," Pincus said.
Pincus has Lindsay's parents go through the exercises so they understand what their daughter feels like every day.
On day four, it was time for Lindsay to try it in the real world.
Pincus loaded Lindsay up with caffeine to make her jittery. She took away Lindsay's cell phone and iPod and sent her off on the Boston subway alone. The fear set in quickly.
"I was just like nervous," Lindsay said. "I had a headache."
The next assignment prompted a full-blown panic attack. As Lindsay got her food and sat alone, her anxiety level climbed to what she estimates is a seven on an eight-point scale. But she stayed put and rode the wave of panic until it subsided. Pincus said it was a breakthrough.
On day five, Pincus put Lindsay through her toughest trial yet and sent her on a 90-minute boat tour with no way to escape and no one she knew aboard to turn to if she panicked, but she made it.
"I'm just really excited," Lindsay said. "I mean, we waited a long time for this and you know, I can already feel the difference."
"I think Lindsay has done incredibly well and gotten herself to a point where now, if she continues practicing, she will be cured," Pincus said.
Lindsay came so far that she was able to attend a Jason Mraz concert. Concerts used to bring out intense feelings of anxiety.
"It was really good," Lindsay said. "Today it was easy. I'm planning to go to more concerts and do more things on my own."