Schizoaffective disorder is a form of psychosis and is a mental illness in which a person experiences a combination of schizophrenia symptoms. People affected often have hallucinations or delusions, as well as mood disorder symptoms such as mania or depression. Our patient, Lynne Fisher, had her life turned upside down by the onset of this illness, and battled through five years of symptoms to find a treatment plan that enables her to have a constructive and happy life. Myth or Medicine: Are people with serious mental illness more prone to violence? Second Opinion 5: Five reasons to consult a mental health professional.