Imagine washing your hands up to 40 times a day, all because you are worried about germs.
You avoid touching anything that you deem dirty, and when you accidentally do, you get distressed and clean your hands until the skin becomes severely dry or even bleeds.
It may be hard to understand the beliefs that obsessive compulsive disorder (OCD) bring about.
This is a brain disorder that causes problems in information processing.
The repetitive actions, known as compulsions, can be taxing, yet the patient has to carry them out to ease his anxiety.
Both adults and children can have OCD, though younger patients are often unable to realise that their symptoms are abnormal.
So they are more unwilling to seek help, said Dr Adrian Loh, a visiting consultant at the department of child and adolescent psychiatry at the Institute of Mental Health (IMH).
It is not known what causes OCD.
What puts people at higher risk are an anxious temperament, a family history of OCD, a high number of stressors and insufficient levels of the brain chemical serotonin, said Ms Haanusia Prithivi Raj, a senior clinical psychologist at the same department at IMH.
One in 33 people suffers from OCD in his or her lifetime, according to the Singapore Mental Health Study.
Every year, the IMH Child Guidance Clinics treat 100 to 200 children and adolescents with OCD.
Younger patients often have compulsions, such as touching objects in a certain way.
“In many cases, they say it just feels right,” said Dr Loh, adding that this can frustrate parents.
Some children with OCD may also suffer from anxiety disorders, attention deficit hyperactivity disorder or autism, he said.
Ms Haanusia shares tips for caregivers and schoolteachers of young people with OCD.