How do mood symptoms differentiate schizophrenia from schizoaffective disorder?

• A. The correct statement about mood symptoms is that schizophrenia has mood symptoms present but not dominant; schizoaffective disorder features a major mood episode concurrent with psychotic symptoms with substantial mood symptoms independent of psychosis.
• B. Schizophrenia requires mood symptoms to be dominant.
• C. Schizoaffective has no psychotic symptoms.
• D. They are identical conditions.

Answer: (A)

The idea being tested is how mood symptoms relate to psychotic symptoms over the course of the illness. In schizophrenia, mood symptoms can appear but they are not the main driver of the illness; the psychotic features—delusions, hallucinations, disorganized thinking—predominate and mood disturbances do not reach the level of a major mood episode for most of the illness.

In schizoaffective disorder, there is a major mood episode (depressive or manic) that occurs concurrently with psychotic symptoms, and these mood symptoms are substantial and persist across illness periods. Crucially, there are times when psychotic symptoms occur without a prominent mood episode, which helps distinguish schizoaffective disorder from a pure mood disorder with psychotic features.

So the best statement is the one that says schizophrenia can have mood symptoms, but they’re not dominant; schizoaffective disorder involves a major mood episode occurring with psychotic symptoms and mood symptoms that are substantial beyond the psychosis. The other options misstate the relationships—for example, schizophrenia does not require mood symptoms to be dominant, schizoaffective does involve psychotic symptoms, and the two conditions are not identical.