Well, the Diagnostic Statistics Manual (the premier reference for all things psychiatric) is not online without paying membership to some site or buying it outright. Since I don't teach anymore, I don't want it.
But I did find this very good link about schizophrenia.http://www.surgeongeneral.gov/library/mentalhealth/chapter4/sec4.html
You'll also notice as you peruse the overview I linked to that there are helpful subsections located in the left column there, too.
* Course and Recovery
* Etiology of Schizophrenia
From their site and directly obtained from the DSM IV:
# Characteristic symptoms: Two (or more) of the following, each present for a significant portion of time during a 1-month period (or less if successfully treated):
3. disorganized speech (e.g., frequent derailment or incoherence)
4. grossly disorganized or catatonic behavior
5. negative symptoms, i.e., affective flattening, alogia, or avolition
Note: Only one Criterion A symptom is required if delusions are bizarre or hallucinations consist of a voice keeping up a running commentary on the personís behavior or thoughts, or two or more voices conversing with each other.
The table goes on to include the rest of the criteria on duration, social and occupational dysfunction, etc. It's an informative clear concise read.
I've not known a person who is afflicted with this. But I hope this helps you.