A 52-year-old man with raw, chapped hands is referred to a psychiatrist by his primary care doctor. The man reports that he washes his hands repeatedly, spending up to 4 hours a day, using abrasive cleansers and scalding hot water. Although he admits that his hands are uncomfortable, he is entirely convinced that unless he washes in this manner he will become gravely ill. A medical workup is unrevealing, and the man takes no medications. What is the most appropriate diagnosis? Delusional disorder, somatic type. Illness anxiety disorder. Obsessive-compulsive disorder, with absent insight. Obsessive-compulsive personality disorder. Generalized anxiety disorder.