A commonly used screening tool for psychopathology, the Brief Symptom Inventory, provides normative data for assessing current mental functioning across multiple domains. Using data from 654 psychiatric inpatients, receiver operating characteristic (ROC) analyses were conducted for three scales, Depression, Paranoid Ideation, and Psychoticism. t ratios identified significant group differences on the Depression scale between patients diagnosed with or without depression but no differences on the Paranoid Ideation and Psychoticism scales between patients diagnosed with or without schizophrenia. Area under the curve for Depression was .65, indicating that the scale improved diagnostic prediction somewhat beyond chance; for Paranoid Ideation, the area was .52 and for Psychoticism, the area was .53, indicating that these two scales did not significantly improve diagnostic prediction beyond chance.