I am curious about the methodology they apply to such patients.

Because how would they know if the patient in question hypothetically has a moment of lucidity in which he/she is able to realize and accept that he/she has a problem in order to move forward with the treatment? But of course, how would they know if that person is not lying and acting in a convenient way just to get out as soon as possible?

I guess you have to analyze the signs in the patient's behavior to confirm if the behavior is genuine, right?