Objective: The Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) is a well-validated tool for neurocognitive assessment in inpatient settings. In 2007, Silverberg et al. developed an Effort Index (EI) to assess for performance validity within the RBANS. Results from validation studies are generally positive, with the exception of high misclassification rates in certain geriatric settings. Although the RBANS has been validated on inpatient psychiatric samples, the utility of the EI in this setting is unknown. Method: Archival data from 72 individuals hospitalized for a variety of acute psychiatric disturbances were examined. Twenty-eight individuals age >66 were excluded to minimize the confounding variable of dementia. The remaining 44 patients were included and classified as producing either valid (n = 35) or invalid (n = 9) profiles using a TOMM Trial 1 raw score cutoff of <40. Diagnostic categories included Mood Disorders (n = 25), Psychotic Disorders (n = 11), and Other Psychiatric Disorders (n = 8). Results: A one-way ANOVA revealed no significant differences in demographic variables between the groups. Use of a >3 EI cutoff resulted in 92% specificity and 56% sensitivity. Conclusion(s): The aforementioned RBANS EI cutoff achieved a specificity rate greater than 90% and a satisfactory sensitivity rate in this acute psychiatric inpatient setting. These results are promising but because our sample size is relatively small, we recommend additional validation studies. Future directions are discussed.