SCL 90-R interpretation and brain tumour: a correction factor?
Abstract
Objective : Determine whether spurious SCL 90 R profiles resulting from endorsement of neurologic treatment items can be corrected and still retain ecological validity. Design : The proportion of subjects item endorsement was compared with the adult non patient norm group. Items with discriminative power chi2 > 25, p < 0.001 and endorsement by at least 25 of subjects underwent principal components analysis with somatic treatment and psychiatric factors identified. Items in the somatic treatment factor were extracted as the corrective factor. The resultant corrected T scores were plotted against original SCL 90 R profiles. Setting : University medical centre. Patients : Thirty community dwelling adults with biopsy confirmed malignant brain tumours referred by their treating physician for evaluation prior to aggressive treatment. Interventions : The SCL 90 R was part of a neuropsychological test battery. Main outcome measure : The SCL 90 R was selected prior to data collection because it is the second most frequently used psychosocial instrument in medical settings, yet has demonstrated attenuated validity with neurologic patients. Results : Extraction of 10 somatic treatment items resulted in lower profiles on Somatization, Obsessive Compulsive, Depression, and Anxiety dimensions and the global indicators. However, clinical caseness for individuals remained greater than indicated by clinical interview. Conclusion : Correction for SCL 90 R neurologic treatment items resulted in reduced sensitivity and poorer ecological validity.