Answer: D – Obsessive compulsive disorder is an anxiety in which a person experiences compulsions or obsessions that interfere with normal life functioning. An individual with this psychotic disorder will constantly think about one thing over and over. People who are depressed appear to be more likely to develop these intrusive thoughts. The OCD is the response to such ideas, which may have a biological base for emotional response. This disorder is resistant to treatment and will require therapy for a long length of time.