I need the MOST COMMON symptoms, not all of the symptoms. just the symptoms that most people with this illness share.
Agorophobia, delusions {"seeing or hearing things"} Manic Depression,and a lot of times intense panic disorder or paranoia.
Look up the DSM-IV. It'll give you a pretty good overview of it, and look up psychosis, as well. to be honest, though, people with schizophrenia are quite varied and it also depends on what stage of schizophrenia they're at. If I had to take a guess at the most common signs and symptoms, though, I'd say: hallucinations (visual, auditory, olfactory, etc.), delusions, thought disorder, and flat or blunted affect. again, this is a guess and very vague and generalized.
Usually people start looking at diagnosing someone with it when they think they can hear things or hear people talking about them that clearly are not. possible visual hallucinations too but the most common symptom is probably hearing voices…