No brain washing was involved, just detention.
(Netscape just cut out on me, so back on IE)
I remember reading about North Korean brainwashing many years ago...
What impressed me the most was their finding that if you separate the leaders from a group of POW's that the ones left will pretty much do or believe anything they are told.
They would watch a group and then take out of the group anyone who showed any initiative, like suggesting making latrines or picking up the garbage, etc.
The part that rocked me was that only 1-2% of the men needed to be removed, that only that few showed any initiative or leadership.
That made me a lot more understanding of Patty Hearst when that situation arose.
Back to the mental institutions...
I wonder (assuming this happened) if FDR got the idea from Stalin.
Meanwhile, my husband has been watching a documentary about FDR and Stalin in WWII and what impressed him most was how old and decrepit FDR was. Not just at the end, but before. Wonders how much grief we endured with the Soviets after the war was due to FDR not being physically or mentally strong enough to stand up to Stalin during the war.