Obsessive Compulsive Disorder.
Obsessive-Compulsive disorder describes when people are experiencing intense recurrent and unwanted or intrussive thoughts (obsession) which cause anxiety or distress and rituals (compulsive behaviors) that serve to eliminate or reduce the anxiety, such as handwashing, counting, checking, or cleaning/organizing.
The intrussive thoughts can be frightening such as when driving over a bridge where the patient is thinking or feeling intensely like they should drive off the bridge. The patient, who is not suicidal, is baffled by this unwanted thought that just popped in their head.
Sometimes the compulsions or rituals involves numbers, like adding up numbers or car tags, wanting the numbers to be even nmbers and being distressed when it's not.
Sometimes the compulsions or rituals are to do with particular colors.
Germs are another common area people have problems with, they cant therefore use public bathrooms, open doors with tissue paper, carry germex and other hand santizers around, wash their hands until the skin is raw and chapped.
What can be done?
Again, there is particular help for this.
Cognitive behavioral therapy has been documented to be very helpful with this. Other individual type therapies will sometimes be recommended to alleviate underlying deprssion and stressors.
Sometimes a combination of anxiety type medicines and anti depressants are prescribed to alleviate symptoms.