A clinical comparison simulation study using the Inventory of Problems-29 (IOP-29) with the Center for Epidemiologic Studies Depression Scale (CES-D) in Lithuania.

This article contributes to the growing research on the validity of the recently developed, Inventory of Problems - 29 (IOP-29) in the discrimination of feigned from bona fide mental or cognitive disorders. Specifically, we first developed a Lithuanian version of the IOP-29 and tested its validity on a sample of 50 depressed patients and 50 healthy volunteers instructed to feign depression. Next, we reviewed all previously published IOP-29 studies reporting on depression-related presentations ( = 5), and compared our results against previously reported findings. Statistical analyses showed that the Lithuanian IOP-29 discriminated almost perfectly between genuine and experimentally feigned major depression, with Area Under the Curve (AUC) = .98 ( = .01) and Cohen's  = 3.31. When compared to previously published IOP-29 literature on this same topic, these findings may be characterized as similar or perhaps slightly more encouraging. Indeed, across all international, empirical studies considered in this article, Cohen's ranged from 1.80 to 4.30, and AUC ranged from .89 to .99. Taken together, these findings contribute to supporting the strong validity and cross-cultural applicability of the IOP-29. They also provide additional support for its use in forensic evaluations.