Methods to reduce false reporting of substance abstinence in clinical research.

Objectives: Substance use may influence study results in human subjects research. This study aims to report the concordance between self-report and biochemical assessments of substance use and test the effect of methods to reduce false reports of abstinence in trauma-exposed women participating in a research study.

Methods: In this pilot study, substance use was assessed during telephone prescreening and via self-report and biochemical verification (i.e., urine toxicology and alcohol breathalyzer tests) at an in-person evaluation. Due to the high number of participants who tested positive for substances despite self-reporting abstinence during prescreening, study procedures were modified to disincentivize false self-reports of substance use two thirds of the way through recruitment. New potential participants were explicitly informed during prescreening and informed consent that a positive drug or alcohol test during screening would result in exclusion from the study and withholding of payment.

Results: Prior to modifying study methods, 20% of participants who had reported abstinence during the telephone prescreen had a positive substance use test at the in-person visit. Modifying study procedures resulted in an 81% decrease in positive substance use assessments.

Conclusions: Adoption of this methodology may decrease inadvertent confounding of clinical research outcomes by undetected and/or misreported substance use.