Is the door locked? Is the stove off? What about the alarm: Is it set? These are questions many of us ask ourselves every day. And once we check, the thoughts subside.
But for people who suffer from obsessive compulsive disorder, these thoughts become obsessions, which haunt them night and day, and can lead to sometimes bizarre rituals that start to control their lives.
OCD is a devastating illness that affects about 5 million Americans, and about 1 million are children, according to the OC Foundation. People living with OCD are not only tortured by obsessions and repetitive rituals but by recurrent and persistent unwanted thoughts and images. It's a crippling disease that is often misunderstood.
"Primetime" followed children who are battling OCD and their families from the doctor's office to their homesas they attempted to overcome the stigmas associated with the disorder and reclaim their lives.
For 15-year-old Bridget of New Jersey, her personal battle was about getting back home.
Though Bridget looked like a typical teenager on the outside, inside she wrestled to break free from the unbearable fear that her own family was somehow contaminated and could infect her.
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"Think about it as being something that's dirty -- radiation or something like that. It spreads," explained Allen Weg, a licensed psychologist and the founder and director of Stress Anxiety Services of New Jersey and Pennsylvania. "And so when this thing touches the thing that's contaminated, then that thing, that new thing becomes contaminated."
But things weren't always that way for Bridget, a happy child who loved to swim and enjoyed being around her family. Enrolled in the gifted program and a star student in school, she brought much pride to her parents.
Bridget's first signs of compulsive behavior came at age 11, with what her mother, Karen, described as a need to be perfect in school.
"Everything had to be a 100, or she had to know every spelling word," Karen said. "Then all of a sudden she started to notice that her books had to be in a certain place, and she didn't want certain things touched."
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Sixth grade was a struggle for Bridget, but she said she believed things were getting better, and she was able to stop taking medication in eighth grade.
"Then [in] eighth grade, miraculously, it was pretty much better. So I stopped taking my medicine, I stopped going to the therapist. And then over the summer between eighth grade and freshman year, that's when this came up," Bridget told ABC News.
When Bridget entered high school, her OCD returned, morphing into a more severe form. She feared that her family was contaminated, which prevented her own parents from touching her.
Karen struggled to find her daughter the right help, taking her to see a therapist in the fall of 2008. But four months into treatment, Bridget showed no signs of getting better, and it was becoming harder and harder for her to be around her family.
In September 2008, because the constant fear of her family consumed her, Bridget had to move out of her house and in with her grandmother. The move was especially trying on her mother, Karen, who drove between her home in Aberdeen, N.J., to Bridget's grandmother's home, which was nearly an hour away.