[Nogrod]

Fatty Bolger is one of the most sane hobbits there is fex. by not willing to take part on that really crazy adventure - and being the organizer of all things there in the beginning requires a steady and composed mind anyway. It's hard to call his kind deranged, mad or insane - or psychotic. Choosing him would be insane - haha, an argument for picking him!

Ted Sandyman and Lobelia may be baddies of some sort but they are not insane. They are just people trying to capitulate from others - normal twenty-first century people that is. Well, one could describe our time as an insane age so therefore why not?

Tar Atanamir could make it into the same slot with Ted and Lobelia, only he is not a commoner on some far-away land aside from the civilization.
but he was a greedy and "unwilling" (as they called him) to die but that I think - looking at it from a mortal POV - is no sign of being deranged or mad. Who of us wishes to die?

Angband or Mouth of Sauron insane? No. Deranged, mad, psychotic? Not either. They were working perfectly reasonably and to the point. Bad, evil, corruptive? Yes - but those are other Red Taters than "insane".

Númenor being insane, psychotic, deranged or mad? Now excuse me as a great fan of Númenor! It's the heyday of humanity! Now some of it's rulers - late in their history - might have been too full of themselves and building the path to their own undergoing, but that Númenor itself would be something like insane, well no. If you say Númenor is insane you say that Valar were psychotic creating it, or that Eru himself was deranged allowing it's creation - or that Elros was mad - or Elendil or... (pick your favourite Númenorian here)

So I really think it leaves the choices into: Gollum/Smeagol, Denethor, Tom Bombadil, and Thorin Oakenshield.