Patients with schizoaffective disorder have psychotic episodes that resemble schizophrenia but with prominent mood disturbances. Their psychotic symptoms, however, must persist for some time in the absence of any mood syndrome.

Epidemiology

Lifetime prevalence is estimated at 0.5% to 0.8%. Age of onset is similar to schizophrenia (late teens to early 20s). Schizoaffective patients are more likely than schizophrenics but less likely than mood-disordered patients to have a remission after treatment.

Etiology

The etiology of schizoaffective disorder is unknown.
It may be a variant of schizophrenia, a variant of a mood disorder, a distinct psychotic syndrome, or simply superimposed mood disorder and psychotic disorder.

Clinical Manifestations

History and Mental Status Examination Patients with schizoaffective disorder have the typical symptoms of schizophrenia and coincidentally a major mood disturbance, such as a manic or depressive episode. They must also have periods of illness in which they have psychotic symptoms without a major mood disturbance. Mood disturbances need to be present for a substantial portion of the illness.
There are two subtypes of schizoaffective disorder recognized in the DSM-IV, depressive and bipolar, which are determined by the nature of the mood-disturbance episodes.

Differential Diagnosis
Mood disorders with psychotic features, as in mania or psychotic depression, are different from schizoaffective disorder in that schizoaffective patients have persistence (for at least 2 weeks) of the psychotic symptoms after the mood symptoms have resolved.
Schizophrenia is differentiated from schizoaffective disorder by the absence of a prominent mood disorder in the course of the illness.

It is important to distinguish the prominent negative symptoms of the schizophrenic from the lack of energy or anhedonia in the depressed patient with schizoaffective disorder. More distinct symptoms of a mood disturbance (such as depressed mood and sleep disturbance) should indicate a true coincident mood disturbance.

Management

Patients are treated with medications that target the psychosis and the mood disorder. Typically, these patients require the combination of an antipsychotic medication and a mood stabilizer. Mood stabilizers are described in Chapter 13. An antidepressant or electroconvulsive therapy may be needed for an acute depressive episode. Psychosocial treatments are similar for schizoaffective disorder and schizophrenia. Prognosis is better than for schizophrenia and worse than for bipolar disorder or major depression.