Differences between psychotic and nonpsychotic patients on content dimensions of the MMPI Sc scale

This study examined elevated MMPI Sc scores among psychotic and nonpsychotic patients to determine whether homogeneous item-content dimensions could clarify the precise meaning of elevations on scale Sc. A total of 45 psychotic patients were compared with 56 nonpsychotic psychiatric patients on the Harris and Lingoes subscales of the Sc scale. All subjects had T-score elevations on scale Sc greater than or equal to 70. The two criterion groups did not differ on overall scale Sc scores, but a distinctive pattern of subscale scores emerged that discriminated the samples. Psychotic patients obtained significantly higher scores on subscales measuring bizarre thinking and perceived loss of control over impulses and emotions. Conversely, nonpsychotics endorsed significantly more items on subscales concerned with symptoms of depression, anxiety, and thinking difficulties. These data suggest that homogeneous item-content dimensions of the Sc scale provide a means for distinguishing between psychotic and nonpsychotic patients who otherwise appear similar on overall scale Sc.