Germs: 'No Deal' for Host Howie Mandel "Deal or No Deal" host says that his OCD injects "terror" into his life.

Nov. 24, 2009 -- People know Howie Mandel as a comedian, actor and game show host. But what many fans don't know is how much he suffers from a crippling fear of germs -- something he has joked about before, but never spoken seriously about until now.

The 54-year-old "Deal Or No Deal" host suffers from obsessive compulsive disorder or OCD -- a debilitating anxiety disorder that produces inescapable repetitive thoughts.

Like many of the 4 million adults who suffer from OCD, Mandel's most frequent obsession is germs, but can manifest itself in countless ways that trigger a silent loop of the question 'What if...' in his mind.

"I'm always on the verge of death in my head," he told "20/20."

ABC News' David Muir followed Mandel for two weeks behind the scenes on the set of "Deal Or No Deal" in Connecticut, at his beautiful California home, and in his spotless Las Vegas penthouse suite at the MGM Grand, where he performs 40 nights a year.

It is quickly evident that Mandel is a gracious family man who loves to entertain, is living his dream, albeit in constant fear.

On the set, instead of shaking hands, Mandel does the fist bump -- his trademark greeting on "Deal Or No Deal" -- to work around his germ anxiety.

"In my mind [my hand] is like a petri dish. ... Otherwise I would spend the day, as I have in the past in my life in the men's room rubbing and scrubbing and scalding," he said.

Mandel lays out the fist bumping rules to all the contestants that stick out their hands to meet him on the show. But his OCD goes far beyond that.

Off stage, it's all consuming. His makeup artists must use brand new sponges every day. He won't touch his money unless it's been washed. He avoids hand rails like the plague. "Hand rails are my enemy. I never go near a hand rail," he said. Even Mandel's trademark bald head is this way by choice. "This feels so streamlined and so clean," he said.

At times, his "irrational" fears can strike at the most inopportune moments.

"The biggest fear I have is being triggered," he said. "And if I'm triggered and I get some sort of weird thought in my head that can't go, then my day is, is stopped. My life stops."

Mandel is going public with his struggle with his OCD in a humorous autobiography entitled, "Here's the Deal: Don't Touch Me," which hits bookstores today. He reveals the unusual set of rituals and the terrifying role that OCD consumes in his life.

"I once missed an appointment because I left my house, I locked the door. And then I thought, like anybody else, you know, I don't think I locked the door. I just kept going back to the door. And I couldn't stop myself from checking and checking," he recalls.

Mandel checked the lock 32 times before he took his fist and punched the handle.

"I thought if I felt the pain in the door, then I know for certain. But intellectually, I know I had checked the door. So why am I going back? I can't get past the thought, whether it's thoughts that go into your head. Fears. Thoughts, horrible images, or whatever," he said.

Mandel Battles OCD, ADHD as Kid

Born and raised in Toronto, Mandel grew up in a self-described loving family. As long as he can remember, he had an unhealthy fear of germs. He said kids made fun of him because he couldn't tie his shoes.

"Well, I could, but I didn't want to touch it. But I don't want to say I'm afraid to touch it because it's dirty, so I didn't," he recalled.

Because of his fear of germs, Mandel didn't tie his shoes, which made walking difficult. "I would try to keep my shoe on so I would drag one foot behind me, because if I lifted my foot the shoe would come off," he said.

To this day, Mandel will not wear shoes with laces.

It wasn't just OCD that Mandel struggled with; he also battled ADHD and the combination of both would prove to make school unbearable.

Mandel said he grew up feeling isolated. He didn't have many friends, especially in high school. Even though he was always looking for a laugh, and loved to play practical jokes, few others saw the humor.

"I became a pariah. I think the thrust of any child is to try to fit in and be part of it. And I can't tell you how many times my humor, you know, what I thought was humor ended up making me the outsider," he said. "Like I'd be, I go, 'it's a joke.' And they'd go, 'well, what was funny?' And they just thought I was insane."

A pattern of elaborate pranks lead to Mandel being expelled. He never finished high school.

Though his sense of humor wasn't popular, his girlfriend Terry found his brand of humor charming. The two have been married for 30 years.

"When I started dating him, and I really knew the real him, I knew how great he was, and how sweet and wonderful and what a great guy he was," she said. "And then there was that other crazy side, which I said, 'Just don't do any of that crazy stuff to me.' I actually thought a lot of it was funny."

Raising Kids, Family Life With OCD

Thirty-six years after meeting, the couple has raised three children together, but Mandel's OCD has often made it difficult.

"That was tough. He was like, 'Nobody touch them, wash your hands.' The kids, when they were crawling on the floor, everything bothered [him], it was so hard for him," Terry said.

Mandel has even been known to wear a surgical mask and rubber gloves when loved ones are sick. He admits his issues aren't easy on his family.

"She's a saint, because a lot of people would not put up with the crap that I doll out because I can't cope. [Terry] has that understanding. It's just a lot for her to have to deal with," Mandel said.

While Mandel has a hard time touching strangers, he and Terry are still very much romantic. "I have known [her]. She's healthy, she's clean, it's not like a stranger," Mandel said. "I can hold her, I can kiss her… it's not the same."

Thirty Years on the Stage

Mandel has been on the stage for 30 years. His first big break came April 19, 1978, when he took the stage at a small comedy club in Toronto called Yuk Yuk's. He loved to perform and felt at home in the spotlight. So it's no surprise that he soon became the featured act. Terry kept his horoscope from that day, which reads: "Tonight your life will change forever." And it did.

Less than a year later, Mandel did a set at the famous Comedy Store in Los Angeles. From there his career took off. He would go on to make more than 20 appearances on "The Tonight Show with Johnny Carson." He added acting to his resume in the 80s, playing Dr. Wayne Fiscus for six years on the Emmy Award-winning drama, "St. Elsewhere," and delved in film and voice-over work.

Mandel's only unexplored territory as a performer was hosting his own talk show. That opportunity came in 1998 with "The Howie Mandel Show." During this time, Mandel was still publicly shaking hands, but kept a bucket of Purell under his desk.

"I would constantly be soaked with Purell. And I also had my friend as a surgeon and I had a surgical scrub that I would do before and after the show," he said. "My hands were raw and I had no antibodies and I started getting warts and it was -- I was a mess."

The show was canceled after just one season. When Mandel was ready to leave TV, the phone rang; it was a call about "Deal Or No Deal." At first, he turned it down. He said he found the offer insulting. But Terry convinced him otherwise. She told him to take the deal.

Mandel Using 'Deal Or No Deal' Fame to Raise Awareness

"This is probably the most notoriety I've had over a 30-some-odd career," Mandel said.

Mandel is using his new fame to help shed the stigma attached to mental health. He recordered a public service announcement for anxiety disorders and is testifying on Capitol Hill.

"You know, in the middle of a workday, wherever you work in America, if you got up and say, 'I'm gonna go see my dentist,' nobody would even flinch," Mandel said. "But if you got up in the middle of the day and said, 'You know what, I gotta go, I'm having a little issue. I've gotta go to my psychiatrist. I'll be back in an hour.' I think that people would -- 'Did he just say he's going to the psychiatrist?' …There's a stigma."

He told "20/20" that he sees a therapist and is pleased with the anti-anxiety medication that he has been taking for the past two months.

Despite his fear of germs, the "Deal Or No Deal" host still tours the country 200 nights out of the year, performing stand-up comedy. Though staying in hotels is difficult since he won't touch the comforter, the shower floor, or the phone, he said he does it because he feels most at home on stage.

"Regardless of what I do, whether I write a book or whether I act or whether I host, I'll always do stand-up comedy because those moments, that's what I crave," he said. "If I do something funny and I hear a crowd laugh in that moment, we're all sharing the exact same experience and the exact same feeling. And that's the only time when I feel part of the world."

For more information on OCD, visit the Obsessive Compulsive Foundation, the Anxiety Disorders Association of America's Web site, and Howie Mandel's official Web site.