What are the motifs in The Vampire Lestat by Anne Rice?

Immortality and madness are recurring ideas. It is suggested several times throughout Lestat's story that not all vampires are able to cope with immortality. Those that cannot deal with eternity eventually go mad. This first evidence of this is seen in Magnus when he imprisons Lestat and makes him a vampire. From the beginning it is clear that there is something wrong with Magnus. After he makes Lestat a vampire, he passes on the lessons that Lestat must have as if he is in a frenzy, and then he immediately goes into the fire to end his life.