Forced-Choice Tests as Single-Case Experiments in the Differential Diagnosis of Intentional Symptom Distortion

Abstract

Symptom validity testing has become a prolific research field in neuropsychology. Its original and most powerful version is the forced-choice procedure that continues to play an important role because it allows for an experimental approach to test the hypothesis of intentional symptom distortion. When conducting forced-choice tests, below-chance response patterns are considered to be indicative of this type of distortion. In this article, we discuss the rationale behind the forced-choice technique and its historical development. We also present three case vignettes that illustrate the experimental background of forced-choice testing and how it may help to clarify diagnostic issues. The diagnostic considerations in these cases concerned (1) complete memory loss, (2) Ganser syndrome, and (3) dementia. Employing forced-choice methodology, intentional false symptom production could be demonstrated in all three patients. Thus, the cases demonstrate how, in the context of substantial external benefits, forced-choice testing may help to determine whether healthy individuals try to appear psychologically impaired.