Which criterion best distinguishes schizoaffective disorder from schizophrenia?

Which criterion best distinguishes schizoaffective disorder from schizophrenia?

• A. It has a six-month duration requirement only
• B. There is no requirement for mood symptoms
• C. Mood symptoms present for the majority of the illness with a 2+ week period of psychosis without mood symptoms
• D. It requires persistent delusions only

Answer: (C)

Distinguishing schizoaffective disorder from schizophrenia hinges on how mood symptoms relate to psychotic symptoms over the illness. In schizoaffective disorder, mood episodes are present for a substantial portion of the illness, and there must be a period of at least two weeks during which psychotic symptoms occur without a major mood episode. This shows that psychosis can occur independently of mood symptoms, but mood disturbance is still a dominant feature across the illness. That combination—mood symptoms lasting for most of the illness plus a 2+ week window of psychosis without mood symptoms—is what sets schizoaffective disorder apart from schizophrenia and from mood disorders with psychotic features (where psychosis occurs only during mood episodes). So the best choice captures both the predominance of mood symptoms and the independent psychotic period.

Distinguishing schizoaffective disorder from schizophrenia hinges on how mood symptoms relate to psychotic symptoms over the illness. In schizoaffective disorder, mood episodes are present for a substantial portion of the illness, and there must be a period of at least two weeks during which psychotic symptoms occur without a major mood episode. This shows that psychosis can occur independently of mood symptoms, but mood disturbance is still a dominant feature across the illness.

That combination—mood symptoms lasting for most of the illness plus a 2+ week window of psychosis without mood symptoms—is what sets schizoaffective disorder apart from schizophrenia and from mood disorders with psychotic features (where psychosis occurs only during mood episodes).

So the best choice captures both the predominance of mood symptoms and the independent psychotic period.