It seems to corrupt their mind entirely. Right now, we haven't the time nor resources to really fully understand it, much less a cure - though what knowledge we do have... is not promising.

[ He watches the fire for a few moments, brow knitted slightly, but then returns his attention to the other. ]

The Fade is another realm, filled with spirits and demons, and separated by the Veil. We visit when we dream - save for dwarves. My people believe it was once the home of our gods. The Chantry teaches it to be the home of the Black City, which was once the Golden City, and the seat of their god. Either way, Lyrium flows both through this world and the Fade, connecting them, and it is from the connection to the Fade that a mage's power stems.