According to HelpGuide.org:
Obsessive-compulsive disorder (OCD) is an anxiety disorder characterized by uncontrollable, unwanted thoughts and repetitive, ritualized behaviors you feel compelled to perform. If you have OCD, you probably recognize that your obsessive thoughts and compulsive behaviors are irrational – but even so, you feel unable to resist them and break free.
Most people with obsessive-compulsive disorder fall into one of the following categories:
- Washers are afraid of contamination. They usually have cleaning or hand-washing compulsions.
- Checkers repeatedly check things (oven turned off, door locked, etc.) that they associate with harm or danger.
- Doubters and sinners are afraid that if everything isn’t perfect or done just right something terrible will happen or they will be punished.
- Counters and arrangers are obsessed with order and symmetry. They may have superstitions about certain numbers, colors, or arrangements.
- Hoarders fear that something bad will happen if they throw anything away. They compulsively hoard things that they don’t need or use.