An OCD spectrum disorder is a disorder that is different from, but appears to be related to, OCD. Several possible factors point to a relationship between these disorders:
1. The psychological treatments that work for OCD also work for these disorders.
2. The medications that work for OCD also work for these disorders.
3. These disorders have a high comorbidity (co-occurrence) with OCD.
4. Areas in the brain that are affected by OCD are affected by these other disorders.
5. There appears to be a family history of these disorders as well as OCD in many families.
Disorders that are considered to be in the spectrum of OCD are as follows:
1. tic disorders
2. eating disorders
3. impulse-control disorders
4. somatoform disorders
All of these disorders are addressed in other questions.