Episodic OCD

How many here has episodic OCD? And what kind of OCD do you have?
I have Pure O OCD with existential theme (and depression) that comes in episodes with months in between of full remission. It's like i never had OCD. It's really strange.

If your OCD comes in episodes, what do you think causes this? Are there any interesting reserach, scientific articles about this?

This is what i found from some quick searching:
http://www.ncbi.nlm.nih.gov/pubmed/9840370 Episodic course in obsessive-compulsive disorder
http://www.ncbi.nlm.nih.gov/pubmed/17006935 Comparison of clinical characteristics in episodic and chronic obsessive-compulsive disorder.
http://www.ncbi.nlm.nih.gov/pubmed/10626781 Is episodic obsessive compulsive disorder bipolar? A report of four cases.

I have pure O episodic OCD that is existential/philosophical OCD. I’ve had 3 episodes in my life. I’m 42. These occurred at age 24, 33, and 40. They each lasted about 6-8 months.

I don’t have any symptoms of bipolar disorder, and other people throughout my family tree have chronic OCD, including my son.