What is the difference between having schizophrenia and schizoaffective disorder?

Certain Similarities: Schizophrenia is a severe brain disorders in which people interpret reality abnormally. Schizophrenia may result in some combination of hallucinations, delusions, and disordered thinking and behavior. Schizoaffective disorder includes the symptoms of schizophrenia and includes mood disorder symptoms such as depression or mania.

They're similar: Officially, schizophrenia is a thought disorder characterized by psychosis which consists of hallucinations and/or delusions. Schizoaffective disorder is when a person fulfills diagnostic criteria for a mood disorder plus has periods of psychosis during times when the mood disorder symptoms are not present. There are two types of schizoaffective, bipolar & depressed types.

Schizoaffective: Schizoaffective disorder is an extremely serious illness that can be thought of as a combination of schizophrenic (psychosis) and bipolar disorder (the old term being manic depression) with involves extreme mood swings. Schizophrenia is about psychosis, but without mood swings.