That's not even close to being true.

As someone with mental illness, I can tell you that you are very wrong. I have never had any desire to go off of my meds at any time, neither has my mom, friends, or ex boyfriend.

Whether a pyschiatric patient will go off their medication without doctor's orders depends on the patient. Some people do it because it makes them sick. Some do it because they think that because they are 'better' they will stay so when they stop the medication. Some do it because they can't afford the medication. As someone with major depressive disorder and acute chronic GAD I stopped my depression medication several times because of emotional abuse from several family members that centered around them calling me a drug addict. So your statement about "all" mental patients stopping their drugs isn't just false, it is highly presumptuous. It means you are assuming you know enough about every mental patient to say their reason for stopping without a doctor's say so is inadequate.

As someone with major depression, I can answer that. It only takes 1-4 days for the drugs to get out of your system. It can take months to get to therapeutic level.

To add to that- she's crazy, not stupid. A person who honestly believes they don't need their meds, or that their Meds are in fact hurting them, will get VERY creative about hiding the fact they aren't taking them. Plus, if her biochemistry shifted, it might have been the meds just stopped working, and neither she or the OP noticed until it was too late. I doubt that's the case here, but it can happen.

they will just put her into a mental illness ward .

What makes you think Op posted this immediately after finding this out?

Well, this app is FML.