Psychotic depression (PD) is classified as a subtype of severe depression in the current diagnostic manuals. Accordingly, it is a common conception among psychiatrists that psychotic features in depression arise as a consequence of depressive severity. The aim of this study was to determine whether the severity of depressive and psychotic symptoms correlate in accordance with this "severity-psychosis" hypothesis and to detect potential differences in the clinical features of PD and non-psychotic depression (non-PD).