A 21-year-old unmarried man has near-daily intrusive thoughts that his neighbors knock on his door at night. He tells the PMHNP he knows this knocking is just his "imagination" because the neighbors work nights and are not home. However, he feels compelled to get out of bed and open the door, no matter what time it is. He opens and closes the door repeatedly for at least an hour, sometimes longer. He says he has had this problem "in the past" and did not seek help for it. This time it has been going on at least 6 months and is becoming "problematic." It is interfering with his ability to get a good night's sleep, and he is having problems at work. His roommate is also very troubled by it. The PMHNP will diagnose him with which of the following?

Choice A reason: This is correct. The patient demonstrates both obsessions (intrusive thoughts about knocking) and compulsions (repetitive checking behavior). The duration exceeds six months and causes functional impairment in sleep and work, fulfilling DSM-5 criteria for OCD. Choice B reason: Generalized anxiety disorder involves excessive worry across multiple domains but does not include specific compulsive behaviors performed in response to intrusive thoughts. Choice C reason: Schizophrenia is characterized by psychosis, including delusions, hallucinations, and disorganized thinking. The patient recognizes that the knocking is imagined, which is inconsistent with schizophrenia. Choice D reason: Agoraphobia involves fear of being in situations where escape might be difficult. The patient’s symptoms are not related to avoidance of public spaces or panic attacks in such settings.