How can I tell if I'm schizophrenic?

Seek evaluation. I would start with an appointment with a board certified psychiatrist and then try and answer all of the questions you are asked as openly and as honestly as possible. That is the best way for a person to be able to determine if he or she has schizophtenia.
See a psychiatrist. Schizophrenia is a chronic mental disorder characterized by hallucinations and delusions. There are 3different subtypes, but the most common is paranoid.