May 17, 2012 -- They are a mother and daughter who consider each other best friends. And yet, Bernadette and her 14-year-old daughter, Taylor, who asked that "20/20" not reveal their last names, don't eat meals together, don't share any activities and don't even speak to each other. It's all because everyday sounds Bernadette makes -- clearing her throat or sighing -- can send Taylor to the brink.
"It's like an almost undescribable amount of anger and, like, rage that I just can't control," Taylor told "20/20."
Taylor suffers from misophonia, a mysterious condition whose name literally means "hatred of sound." Misophonia makes it difficult to tolerate everyday noises such as chewing, coughing, even breathing. And while many might say they get annoyed at such sounds, for those with misophonia, the consequences of hearing such "trigger" noises are far worse than mere irritation: violence, isolation, depression and even thoughts of suicide.
Taylor has attempted suicide three times -- attempts, she said, that were triggered by anti-depressants that did nothing to help her misophonia.
"I don't want her to give up, 'cause she's tried to give up," said Taylor's sister, Alex. "I just want her to keep moving."
Taylor's symptoms began when she was 8 years old.
"I coughed, and she covered her ears, and she ran away," Bernadette said.
Eventually, it grew much worse.
"She's hit my head against the wall. She's kicked me. She's pushed me," Bernadette said, "just whatever she can [do] to stop the sound from coming from me. "
Once the rages pass, Bernadette said Taylor immediately feels remorse for her behavior. But the teen told "20/20" that when in the grips of such a rage triggered by an offending sound, that "sound will replay in my mind until I get the anger out ... until I somehow get out all my frustration."
Audiologist Marsha Johnson of the Oregon Tinnitus and Hyperacusis Treatment Center is one of the only experts who treats misophonia patients. Johnson said the cause of misophonia is suspected to be a "neurological glitch in a very low level of the brain."
For people with misophonia, certain noises, she said, trigger a reaction similar to what others might experience when stung by a bee.
"You have to get that away from you, right now," she said. "It's very intense."
But not everyone's reactions are as devastating as Taylor's. Kelly Ripa, host of the talk show "Live With Kelly," announced last year that she believes she has misophonia.
"As early as I can remember, certain sounds of eating would bother me," she told "20/20."
At the dinner table with her husband and children, the sounds of chomping, slurping or even swallowing is enough to almost set Ripa off.
"My gut reaction is to yell, but I control that," she said.
Still, she added, "if my husband eats a peach, I have to leave the room."
Bernadette and Taylor find themselves in separate rooms most of the time. When they are face to face, they communicate by passing notes or with a form of charades ... but even that doesn't last long. During one recent "conversation," the sound of Bernadette swallowing was enough to prompt Taylor to ask her mother to leave.
Taylor's condition hasn't just affected her relationship with her mother; it's upended her whole life. Unable to tolerate sounds like chewing, coughing and sniffling, she had to leave her friends at school and began attending an alternative school with limited hours. And then there were the suicide attempts; the most recent one happened in January.
"She's the sweetest girl that you'll ever meet. The kindest," Bernadette said. "And the saddest part is her crying out to me, saying, 'Mommy, what's happening to me? What is this?'"
Today, Taylor hides from sound, even sleeping with headphones on.
"I'd like to be able to go to school and school events, participate in all my sports that I used to love, and hang out with friends and go out to dinner with my family," she told "20/20."
But, she said, "90 percent of my life is probably in my bedroom."
There has been a positive step recently: Taylor returned to a dance class she loves. The loud music that plays during the class muffles the sounds that could upset her.
Taylor has also been encouraged to try white noise ear buds and Cognitive Behavioral Therapy, a form of psychotherapy that aims to help patients by changing their thinking and emotional responses.
Bernadette remains hopeful.
"I feel that Taylor's such a strong, courageous kid, that she is going to help find a cure. And that's what I keep in the back of my head," she said. "She's going to be part of this. She's going to help others."
Watch the full story on "20/20" Friday at 10 p.m. ET.