Thanks for all your comments, so far so good she seems to be tolerating it.She is under weight so the docs are not concerned about the weight gain, in fact that would be a good thing.
i've used risperidone 1mg from the moment i fell ill in 2002, i.e. for 7 consecutive years now, in fact as IL said it helped my OCD. only in 2006 that i thought i was ok and needed no drugs anymore so i stopped it and lived on anafranil (tricyclic AD) but it didn't take me more than 3 months to turn manic and dx bipolar.
So whereas it's an atypical AP but it also possesses a stabilization property. Since it was one of the oldest produced atypicals and perhaps the oldest even, most pdocs start by it along with an anxiolytic. so i would go for it so long that she doesn't complain from it. as to side effects, like the others some weight gain of course.
for mixed states, i found seroquel very effective by all means, it stops it immediately.
i really have no clue why a pdoc prefers a certain AP than another, i presume it's trial and error as one of them told me. As to why the pdoc didn't recommended an AC say rather an AP to start with, i suppose because she is very young.
good luck
As an antipsychotic yes. But I needed a mood stabilizer as well. But then again I have schizoaffective. I did have a cousin though who as a teenager was diagnosed with anorexia and it was connected to OCD and she stablized on Risperdal. Risperdal does have mood stabilization properties though and is approved for that usage so see what happens.
I was put on it and only took it twice and was taken off of it due to it's side effects.