Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. The obsessive compulsive spectrum is a model of medical classification where various psychiatric, neurological and/or medical conditions are described as existing on a spectrum of conditions related to obsessive compulsive disorder (OCD). The model suggests that many conditions overlap with OCD in symptomatic profile, demographics, family history, neurobiology, comorbidity, clinical course and response to various pharmacotherapies. Conditions described as being on the spectrum are sometimes referred to as obsessive compulsive spectrum disorders.