Empirical investigations on the reliability and the value for differential diagnosis of 21 clinical symptoms of disturbed states of consciousness.

Two groups of patients in disturbed states of consciousness (DSC's) were compared with three groups of patients in clear states of consciousness (CSC's): demented, schizophrenic, and non-psychotic patients. In each of the groups, 15 patients were evaluated for 21 "objective" symptoms; each patient was evaluated by two psychiatrists. In this way, reliable symptoms were sought out which could discriminate: 1) elderly patients in DSC's from elderly demented but clear patients; and 2) schizophrenic patients from patients in DSC's caused by either withdrawal states after abuse of alcohol or barbiturates, or psychogenic psychoses. Reliable and discriminating symptoms were found. However, different symptoms discriminated when patients in different diagnostic groups were compared. Three kinds of discriminating values of a symptom may be distinguished from one another: 1) only the presence of a symptom is informative; 2) only its absence is informative; 3) both presence and absence of the symptom are informative.