What term would you use to describe someone that believes in conspiracy theories?

I don’t mean like a schizophrenic or a paranoid I mean like is it a conspiracist? Is that the person that belies in the theory or is behind a conspiracy? I’m not a retard I have checked the dictionary but it just said “One that holds a conspiracy theory.” Which is kind of ambiguous…. Could anyone shed any light please?

A conspiracist or conspiratorialist is a person who believes in or supports a conspiracy theory.

http://dictionary.reference.com/browse/conspiracist