I think it's a little of both. Semirhage taunted Rand about the voices in his head being indicative of Taint madness. Truth, fucking with his head, or a little of both? Ishy's lies were often based on a grain of truth.
This is where part of my theory / headcannon comes into play. (Part of a larger more comprehensive theory about this particular Third Age I've been kicking around but never got to fully flesh out.)
I think that basically all the madness (voices and such) comes from the Taint breaking down walls between lives. It explains Fedwin Morr having the mind of a child: if in one of his past lives he died as a child, then if he were to basically merge with that life (similar to what happened during Veins of Gold, but also similar to what almost happened when Rand attached Rhavin and he almost became LTT) and that child's life took over the body, he would have the mind of a child.
I think it also explains why someone wouldn't go mad: either understanding the other lives that the Taint is letting them access (and accepting this ala Rand/LTT) or, a situation where someone happened to not have a past life (I assume new souls come into existence periodically, and that not everyone is re-born).
Yes, but I would only say this is true after Veins of Gold. Prior to this, he's not really LTT is he?
I think we're in agreement it's the same soul. But I guess the question is, whether they're just a single person and the voice is a figment of Rand's imagination as an explanation for the memories, or, whether the voice is truly a second person, who merges to become a single unified individual after Veins of Gold.
I tend to think the latter. And that if Rand had never channeled: ie if he'd been stilled (assuming the Patten allowed), then he'd never had this second voice.
