Re: What was TNG's very best 'Mindscrew Episode'?
Frame of Mind is probably going to be your winner. I guess you could include "Dark Page" to that list. It seems to be a lesser referenced episode but I though it was executed very well while letting L'waxana finally endear herself to the audience. I still get choked up when she has to relive the Kestra drowning. It was a very powerful scene and a wonderful performance by Majel.
Searching for something, a million miles and a ways to go.