These are simply mixed vampires.  They are part psi, and part sang. The easiest way for me to explain it is a Psi the craves blood. They have all the powers of a Psi, (but weaker, the have problems projecting and linking.) I would suggest that a person that feels symtoms of both, should read up on Psi's AND sangs. Yes, that makes things harder, but it's worth it.