Schizophrenia is a mental illness that affects Humans. A person with this disease may have delusions and see hallucinations. Schizophrenia is a hereditary disease (i.e. one that can be inherited). It cannot be cured but can be treated with medications.
Kelownan scientists including Dr. Kieran and Dr. Tomis Lee, who were working on the Kelownan Naquadria bomb suffered from schizophrenia after being exposed to excessive quantities of Naquadria radiation. (SG1: "Shadow Play")