Schizoaffective disorder is a mental disorder that combines the symptoms of mood disorder and schizophrenia. Both symptoms are prominent. The illness usually begins in early adulthood, and is more common in women.

There are two sub-types of schizoaffective disorder: the bipolar type and the depressive type. The bipolar type has a better prognosis than the depressive type, which can have a residual defect with the passing of time. Bipolar schizoaffective disorder is more similar to bipolar disorder than schizophrenia. People with bipolar disorder may also suffer from isolated episodes of schizoaffective disorders.

People that have a schizoaffective disorder have symptoms of schizophrenia, such as bizarre delusions, hallucinations, and disorganized speech or behaviour, as well as mood disorders, all at the same time. However, there will usually be periods of at least two weeks with psychotic features, but with an absence of mood disorders (such as a major depression or a manic or mixed state episode).