Logical arguments don't help unless you're coming out of the psychosis already....honestly the best way to preserve your relationship is not to agree or disagree with what she's saying for as long as you can....but if she directly asks your opinion then be completely honest. There is something called reality testing that can be done by the patient but not directed by you......

Regarding how long it will take to resolve....honestly have only seen one other obvious case caused by ADHD meds here on these boards and in that case it was a kid, his mom was vehement that he stay on the meds and added an antipsychotic instead. Please keep us updated on her progress.

As far as communication you may want to look into the methods of Xavier amadoor.....he's got books etc.