(1) the functional relationship between obsessions and compulsions

(2) whether neutralizing thoughts are obsessions or compulsions

(3) the extent to which obsessive-compulsives recognize their obsessive fears as senseless

In addition, issues of comorbidity and differential diagnoses are reviewed. Specifically, we consider the relationship of obsessive-compulsive disorder to depression, simple phobia and generalized anxiety disorder, delusional disorder, hypochondriasis, obsessive-compulsive personality disorder, tic disorder, and impulse control disorders. Three case examples are included to illustrate the symptoms of OCD.