Depressive factors and their relationships with other symptom domains in schizophrenia, schizoaffective disorder, and psychotic depression.

Relationships among different symptom domains were investigated in patients with acute exacerbation of schizophrenia with depressive symptoms, psychotic depression, or schizoaffective disorder, depressive subtype. Scores for depression and depressive factors were correlated with positive, negative, and extrapyramidal symptoms within diagnostic categories. No between-group differences in the relationship of different symptom domains could be found, and no substantial relationship between depression and positive symptoms could be revealed in any diagnostic subgroup. Only the retardation factor of depression showed a significant overlap with negative symptoms; depressive core symptoms did not. Core symptoms of depression were independent from other symptoms in all investigated diagnostic groups. Depression seems to represent a heterogeneous symptom domain with unique relationships of components to positive and negative symptoms across nosological borders. A more differentiated assessment, analysis, and treatment of depressive symptoms is therefore recommended for patients with combined depressive and psychotic symptoms.