Individuals with OCD are consumed with doubt and uncertainty and find it difficult to endure their doubt and uncertainty. They place a high degree of over-importance to their thoughts, often believe that their thoughts lead to actions, and attempt to have absolute control over their thinking. They tend to have an inflated sense of responsibility over negative events and situations and are often consumed with feelings of anxiety, guilt, and shame. OCD is often misdiagnosed given that the focus of fear can vary widely among individual sufferers. OCD is also often confused with obsessive compulsive personality disorder (OCDP).
Cognitive behavior therapists help patients accept symptoms of OCD as part of their illness and guide them to realize that obsessional content is irrelevant, is not predictive of future events, does not reflect poorly on their character, and that their attempts to stop their obsessional thoughts are not only unsuccessful, but can backfire by making those thoughts increase in frequency. Patients are helped to confront situations and and events they fear until they learn that they are not in heightened danger and that they can cope with uncertainty and distress.
Further discussion and explanation on understanding and treating individuals with OCD can be found in this two part article by Dr. Lata McGinn: