Objective: The purpose of this study was to investigate the possibility of creating a new scale on the Personality Assessment Inventory (PAI) to assess for ADHD-like symptomatology. Method: Two approaches to scale development were compared: (a) stepwise regression using PAI scales and subscales as predictors and the CAARS-H index as the dependent variable and (b) a MANOVA using discharge diagnosis as the grouping variable and PAI scales and subscales as the dependent variables. Results: Stepwise regression identified six PAI scales and subscales (PIM, RXR, SOM-S, ARD-T, MAN-A, and SCZ-T) that were responsible for a large proportion of variance (39%) in the CAARS-H index, and the MANOVA also identified six subscales that significantly differed between those clients eventually diagnosed with ADHD and those not diagnosed (ANT-S, SCZ-T, MAN-A, ANX-C, BOR-S, and MAN-G). Conclusion: Although each set produced statistically significant findings, neither produced high correct classification rates in the eventual diagnosis of ADHD.