I think the interesting thing is how it is literally impossible to judge his sincerity.

For all we know, he could have given us a 100% spot-on description of psychopathy, or he could be lying through his teeth - without experiencing his life, we have no way of knowing the difference.

I suppose this is possible for /any/ self-description of the internal state of a human mind, but this particular condition obviously muddies the water to an extreme degree.