Maedhros and Gwindor

[Elemmírë]

Okay. This has been bothering me for a while. If there's an old thread on it, I'm sorry, but I couldn't find it.

The Silmarillion:

At first his own people did not know Gwindor, who went out young and strong, and returned now seeming as one of the aged among mortal men…

The Lost Road and Other Writings:

Maidros the chief of Feanor's sons did deeds of surpassing valor, and the Orcs could not endure the light of his face; for since his torment upon Thangorodrim his spirit burned with a white fire within, and he was as one that returneth from the dead, keen and terrible; and they fled before him.

After returning from Angband, Gwindor is only a shadow of his former self, while Maedhros, if anything, seems stronger and enhanced because of it. Physically, why are they so different afterwards? Surely Gwindor's torment could not have been worse than Maedhros's. Mentally, was Maedhros more negatively affected than it seems, and is there any evidence?

Any ideas?