A subscale for negative symptoms from the Comprehensive Psychopathological Rating Scale (CPRS): a comparison with the Schedule for Assessment of Negative Symptoms (SANS).

The Comprehensive Psychopathological Rating Scale (CPRS) was used to determine symptomatology in 145 schizophrenic patients. In 40 of these patients the Schedule for Assessment of Negative Symptoms (SANS) was also applied in order to determine which items in the CPRS represent negative schizophrenic symptoms. Of the patients, 115 were drug-free and 30 were treated with major tranquilizers at the time of the rating. A principal component analysis with oblique solution and Varimax rotation grouped the items from CPRS into ten factors. These factors were subsequently correlated to the total scores of the SANS. When a factor showed a positive correlation with the SANS, the individual items within the factor were examined for correlation to both the subscales and the total SANS scores. Of the 33 items, 5 used in the CPRS showed a positive correlation with the SANS and were therefore considered to represent negative symptomatology in schizophrenia. These items were withdrawal, reduced speech, lack of appropriate emotions, slowness of movements and indecision. The items were grouped as a negative symptom subscale in the CPRS.