Relative efficacy of the SC-O, P-O, P-N, and SC MMPI scales in differentiating brain-damaged, brain-damaged schizophrenic, schizophrenic, and somatoform disorders in an outpatient setting

Abstract

This study examined the efficacy of the Schizophrenic‐Organicity (SC‐O), Psychiatric‐Organic (P‐O), the Pseudo‐Neurological (P‐N), and the Schizophrenia (SC) MMPI subscales in differentiating the following four groups of outpatients: brain‐damaged (n = 35, brain‐damaged schizophrenics (n = 10), non‐brain‐damaged schizophrenics (n = 15), and somatoform disorders (n = 45). Both unmatched and matched samples were used in the analysis, and cut‐off scores were obtained. In an unmatched sample, results suggested that the SC scale was useful in differentiating braindamaged schizophrenics from brain‐damaged and somatoform disorders. With matched samples, the SC differentiated brain‐damaged schizophrenics well from other clinical groups, while the P‐O scale differentiated the nonbrain‐damaged schizophrenics from brain‐damaged and somatoform disorders. Furthermore, the P‐N scale discriminated brain‐damaged schizophrenics from non‐brain‐damaged schizophrenics, while the SC‐O scale was no longer significant. Results suggest that caution should be used in generalizing from previous studies (which used inpatient samples) to outpatient populations.