Schizophrenia is a common (1% prevalence worldwide) and commonly misunderstood psychological disorder. Below is a link to a slide presentation I made about paranoid schizophrenia that I used in one of my classes. It is by no means comprehensive but should provide a decent introduction and overview of current beliefs concerning schizophrenia. Feel free to view it (Acrobat Reader is needed) for personal information but the material is copyrighted and is not intended for non-personal use. Please contact me if you would like to use some of the information for non-personal use.
Also, here is a link to a pretty good video explaining schizophrenia: Video link