Schizophrenia no hallucinations?

Is it possible for a schizophrenic to not suffer from audio or visual hallucations? I have a lot of the characteristsics of a schizophrenic but I've never hallucinated before. Some of the problems I did have were delusions, paranoia, felt like people were constantly judging me and there were conspiracies against me. I also had a lot of mood changes including mania and lots of depression. I also have the characteristic of blank facial expression and don't know what to say in groups of people. i socially isolate myself because i am not comfortable in front of people and feel like i have to flee.