In this study, we sought to explore the diagnostic accuracy of the Personality Assessment Inventory (PAI; Morey, 1991) Validity scales (Negative Impression Management [NIM] and Positive Impression Management [PIM]) and indexes (Malingering index, Defensiveness index [DEF]; Morey, 1993, 1996; Cashel Discriminant Function; Cashel, Rogers, Sewell, & Martin-Cannici, 1995; and Rogers Discriminant Function [RDF]; Rogers, Sewell, Morey, & Ustad, 1996) to identify differences in profiles completed by psychiatric inpatients under standardized instructions (Time 1) and after random assignment (Time 2) to a fake good (n=21), fake bad (n=20), or retest (n=21) scenario. Repeated measures analysis of variance revealed a significant interaction effect. Whereas the retest group did not show any significant changes on the PAI variables from Time 1 to Time 2, both faking groups showed changes in expected directions. Discriminant function analyses revealed that NIM, RDF, and lower scores on DEF best differentiated between the faking bad and retest groups. PIM was the only nonredundant significant score discriminating the faking good and retest groups. Cutoffs for these scales and indexes established in prior research were supported using diagnostic efficiency statistics. Results suggest that NIM and RDF in faking bad scenarios and PIM in faking good scenarios are most sensitive to unsophisticated attempts to dissimulate by inpatient psychiatric patients.