Lorazepam Effects on Word Memory Test Performance: A Randomized, Double-Blind, Placebo-Controlled, Crossover Trial

Abstract

The Word Memory Test (WMT) is a common measure of symptom validity. To investigate the effects of acute benzodiazepines on WMT scores, oral lorazepam 2 mg (LOR) and placebo were administered 1 week apart in a randomized, double-blind, placebo-controlled, crossover study. A total of 28 participants completed the study and were administered the WMT during each drug condition. Within-participant comparisons of LOR vs placebo revealed significant LOR effects for Immediate Recognition (p = .007) and Consistency (p = .019), but not Delayed Recognition (p = .085). Significant LOR effects were present for Reaction Time Measures (Immediate Recognition RT, p = .013; Delayed Recognition RT, p = .001; Multiple Choice RT, p = .011) and Delayed Memory scores (Multiple Choice, p = .007; Paired Associates, p = .029; Free Recall, p = .001). A pattern similar to crossover results was detected for LOR vs placebo between-group differences for initial test assessment scores. When examined using publisher recommended cut scores for the principal WMT measures, there were six participants failing the WMT during initial LOR testing; all six subsequently performed in the normal range upon retesting with placebo. One participant failed WMT during placebo and obtained passing scores during LOR. These data indicate that multiple WMT measures may be affected by acute LOR dosing, and provide additional evidence that potential latent variables and their effects on both SVT performance and cognitive function should be part of the clinical decision-making process.

Keywords:

• Symptom validity testing
• Malingering
• Assessment
• Benzodiazepine

Acknowledgment

Funding for this project was provided by GlaxoSmithKline. Drs. Loring, Finney, and Meador, and Mr. Parfitt, have received research support from GlaxoSmithKline. We thank our reviewers for their helpful comments.