My son got tardive dyskinesia when he was stopping risperidone, (it gave him really bad Akathiesia) he was starting olanzapine.

He still has akathesia while on olanzapine. He's been having trouble taking the olanzapine because he says it makes him feel bad. He might start on Invega oral then injections, I'm afraid that he could get worse akathesia or tardive dyskinesia since invega is similar to risperidone. Do you think Saphris zydis would be better for him? He is 21, and has Schizoaffective disorder.