0_Apprentice
So someone I know was diagnosed with obsessive-compulsive disorder. Anything I should be aware of? 
1_Wizard
Well it is a mental disorder where people repeatedly check things, are very routine, and have certain thoughts repeatedly. 
0_Apprentice
Oh I see. Is there different severity levels to it?
1_Wizard
Yes the a scale called the Yale-Brown Obsessive Compulsive Scale is use. 
0_Apprentice
Does it affect a lot of people?