What has taken over David's life is a severe case of obsessive compulsive disorder that causes such anxiety that he is paralyzed by his fears.
"What concerns me is that I will spread contamination," David said.
Correspondent Erin Moriarty has kept a close watch on his life, providing a rare view into the world of obsessive compulsive disorders.
"It's unbelievable how much power this thing has over his mind," said David's mother Jackie.
"I think it's getting harder and harder to get out the longer he's in," Jackie said.
David, who is 27 years old, has been battling OCD since childhood.
"When the first really noticeable symptoms started, he was 8," Jackie recalled. "That was when he first started washing his hands; he'(d) wash for 15 minutes at a time. "
While in college in the fall of 1998, David's fear of contaminating others became so overwhelming that he retreated inside his parents' bathroom. "This is the worst it's ever been," he said then. "I'm sort of in my Howard Hughes phase right now."
48 Hours first met David shortly afterward and gave him a special camera so he could describe his world, one of exhausting rules and rituals, including showers that go on for hours.
He scrubbed the floor, saying, "This is about the seventh time I've done this today."
"I don't have any room in the trash basket so I use the second sink," he said.
And why the 12-hour showers? "I wash myself very very thoroughly," he said.
The cleansing process could last for days, even weeks.
And he had to follow certain rules before he could open the door of the bathroom, he said.
And who set the rules?
"I suppose I do, a part of me does anyway," he said.
David missed appointments and spent two birthdays and three Christmases alone.
But if David was trapped behind that door so were his parents on the other side of it.
"People keep saying, 'I don't know how you do it.' You do what you have to do," said his mother Jackie.
David's mother - a tutor - and his father Paul - a college librarian - had to find creative ways to feed a son who, for months at a time, refused to open his door even a crack.
"It's interesting walking through the grocery store trying to figure out what kind of food is flat enough to go through a half inch space. You get creative," Jackie said.
"You could have a unique cookbook, the only under-the-door cookbook," Paul said in a light-hearted moment.
But don't let the humor fool you; this life was taking its toll.
"I go out and go to work and leave David behind so I get a feel for being more normal, but I am frustrated by continually having to talk to him through the door, have him not let us touch him," Jackie said.
David found wys to pass the time. "Mostly I read the books I get under the door," he said.
And if the phone, books and everything else were removed from the bathroom?
"He'd still be there, if he felt he had to," Jackie said. "This was an attempt to distract him from the fear."
One distraction was playing chess with his father with a board made out of a Styrofoam plate.
"He is so bright, and has so much talent. And he's not being able to use it," Paul said. "That's tough; I know it's painful for him."
By all accounts, David had been a brilliant philosophy student who planned to get a doctorate.
"It looks like there's no end to this," Jackie said. "When I think about the whole picture, what he could be doing and should be doing if this weren't affecting him, that's when I want to sit down and cry."
Jackie needs all the strength she can muster because as David watches the seasons change outside his bathroom window, he is sinking in despair.
"You have to change your clothes and take a shower," David insisted in one interchange as his mother said, "I was three rooms away from you; I wasn't even around the corner."
"I don't feel like I have any dignity anymore," David said. "I'm locked in a bathroom. If I die tomorrow, it wouldn't make any difference because I haven't gotten anything done."
"The longer I'm in here...the harder it's getting," David recorded in a video diary he has been keeping for two years. "It's so frustrating...that sometimes you become extraordinarily angry."
"We have not found a health care professional in this town who understands OCD and can do behavior therapy," Paul said.
Unable to find help close to home, David's parents turned to Dr. Michael Jenike, a psychiatrist who four years ago started country's first inpatient OCD facility near Boston. He hoped to treat David there once he left the bathroom.
For the first time in a long time they felt hope. "Dr. Jenike...as far as I'm concerned...has been our lifeline to sanity," said Jackie.
Jenike uses email and the telphone to provide free advice long distance to David's parents.
"People with OCD, it's almost pure suffering. It's one of the most intense, painful experiences the patients describe. Much worse than physical pain," Dr. Jenike said.
|Dr. Jenike: comfortable on the court.|
He's obviously not a conventional therapist; weekly basketball games with his patients are just part of his approach.
"If doctors do things that are a little weird that they don't expct,...that helps make an alliance with them," Dr. Jenike said.
Dr. Jenike does use traditional counseling sessions and anti-depressant medications.
But what seems to work best for his patients is something called exposure therapy, where they are forced to deal directly with their fears.
"When I touch money, I feel very dirty so I have to wash my hands for at least 15 minutes," said Patricia, who fears she is being contaminated by money. Under the rules of exposure therapy, not only is she not allowed to wash her hands after touching money; she's surrounded by it.
"It's actually torture," Patricia explained. "I feel very anxious at this moment, just looking at the money on my bed."
"These patients are actually courageous," Dr. Jenike explained. "It (is) like us having to stand on the edge of the Empire State Building with our eyes closed and having a doctor say, 'Trust me, this'll make you feel better.'"
What makes treating his patients so challenging, says Dr. Jenike, is that no one in the medical community really knows what causes OCD. Severe cases, such as David's, are often misdiagnosed and misunderstood.
"These are real illnesses that are biologic. Just because we don't understand the illness doesn't mean we should slander the patient," Dr. Jenike said. "To me, all of these disorders, involve the brain."
"I don't think it's a disorder of, you know, toilet training or the way you're raised, or stress, or so forth. I think that those things can really intertwine with it...but I think there's an underlying brain problem of some kind," he noted.
The best research suggests that in people with OCD, there is some kind of "misfiring" in the front part of the brain, the part of the mind that controls planning and judgment and gives healthy people confidence in their decisions. Because of that misfiring, David who's convinced he's contaminated, can't be reassured, no matter how much you try to reason with him.
Because David isn't a threat to himself or others, Dr. Jenike can't force him to get help, but he says it wouldn't work anyway.
Why can't he just pull him out of the bathroom? "Even though it's logical, I just don't know of any cases where it worked," the doctor explained.
Still, Dr. Jenike believes David will get out of the bathroom for treatment because he has seen progress in an even worse case.
Click here to see how David succeeds in leaving the bathroom.