What causes ocd in teens?

OCD cause: Speculation is that it is a combination of genetic vulnerability and interaction with environment. In young people strep infections might lead to OCD symptoms, but antibiotic treatment has not been effective.

OCD: In NOT only teens, OCD is obsessive compulsive disorder, which is comprised of obsessions (repeating unwanted thoughts) and compulsions (ritualistic behaviors to help deal with those thoughts) such as washing hands repeatedly, constantly cleaning, checking locks, and other similar behaviors. Often the emotions behind OCD are based in fear and/or anger that is unresolved and even unverbalized.