Schizoaffective disorder is a psychiatric diagnosis of a neurobiological nature. It describes a condition where both the symptoms of a mood disorder and schizophrenia are present. A person may manifest impairments in the perception or expression of reality, most commonly manifesting as auditory hallucinations, paranoid or bizarre delusions or disorganized speech and thinking, as well as discrete manic and/or depressive episodes in the context of significant social or occupational dysfunction. The disorder usually begins in early adulthood, although, rarely, it is diagnosed in childhood (prior to age 13). Schizoaffective disorder is more common in women than in men. Despite the greater variety of symptoms, the illness course is more episodic and has an overall more favourable outcome (prognosis) than schizophrenia but worse than mood disorders.

There are two types of schizoaffective disorder: the bipolar type and the depressive type. In general, schizoaffective disorder bipolar type, has a better prognosis than the depressive type, which can result in a residual defect with the passing of time.

The mainstay of treatment is pharmacotherapy with an antipsychotic and an antidepressant or mood stabilizer. Dosages of antipsychotics are generally lower than in the early decades of their use. Psychotherapy, vocational and social rehabilitation are also important. In more serious cases—where there is risk to self and others—involuntary hospitalization may be necessary, though hospital stays are less frequent and for shorter periods than they were in previous years.

Some people diagnosed with schizoaffective disorder are likely to be diagnosed with comorbid conditions, including substance abuse.

Children diagnosed with this disorder are highly likey to have other comorbid neurological disorders such as pervasive developmental disorder, autism and learning disabilities.