Obsessive-compulsive disorder primarily causes which of the following?

Obsessive-compulsive disorder (OCD) is characterized by the presence of obsessions and compulsions. Obsessions are intrusive, unwanted thoughts that cause significant anxiety or distress, while compulsions are repetitive behaviors or mental acts that individuals feel compelled to perform in response to their obsessions. These compulsions are often aimed at reducing the anxiety associated with the obsessions or preventing a feared event from occurring.

Thus, the primary features of OCD revolve around these repetitive thoughts (the obsessions) and excessive urges to engage in particular behaviors (the compulsions) to alleviate the distress caused by those thoughts. This aligns directly with the correct answer, as it encapsulates the core experience of individuals with OCD.

Other options, while they may represent symptoms associated with different mental health conditions, do not specifically capture the hallmark experiences of obsessive-compulsive disorder. Memory loss and derealization may be indicative of other disorders like dissociative disorders. Social withdrawal and isolation can be symptoms of various anxiety disorders or depression, but they are not central to the diagnosis of OCD. Heightened emotional responses could reflect a range of emotional disorders but do not specifically define OCD. Hence, focusing on the repetitive thoughts and excessive urges truly represents the essence of this disorder.