Obsessions are intrusive, irrational thoughts: unwanted ideas or impulses that repeatedly well up in a person’s mind. Again and again, the person experiences disturbing thoughts, such as “My hands must be contaminated; I must wash them”; “I may have left the gas stove on”; “I am going to injure my child.”

On one level, the sufferer knows these obsessive thoughts are irrational. But on another level, he or she fears these thoughts might be true. Trying to avoid such thoughts creates great anxiety.

Compulsions are repetitive rituals such as handwashing, counting, checking, hoarding, or arranging. An individual repeats these actions, perhaps feeling momentary relief, but without feeling satisfaction or a sense of completion. People with OCD feel they must perform these compulsive rituals or something bad will happen.

OCD is often described as “a disease of doubt.” Sufferers experience “pathological doubt" because they are unable to distinguish between what is possible, what is probable, and what is unlikely to happen.

People who do the following may have OCD:

  • repeatedly check things, perhaps dozens of times, before feeling secure enough to go to sleep or leave the house. Is the stove off? Is the door locked? Is the alarm set?
  • fear they will harm others. Example: A man’s car hits a pothole on a city street and he fears it was actually a body.
  • feel dirty and contaminated. Example: A woman is fearful of touching her baby because she might contaminate the child.
  • constantly arrange and order things. Example: A child can’t go to sleep unless he lines up all his shoes correctly.
  • are excessively concerned with body imperfections. They insist on numerous plastic surgeries, or spend many, many hours a day body-building.
  • are ruled by numbers, believing that certain numbers represent good and others represent evil.