Explanations for Failure to Detect Effects of a Prescription Medication Disposal Intervention for Rural Adults.

Prescription opioid misuse has had a substantial impact on morbidity and mortality in the United States, but proper disposal of unused medications can reduce the risk of misuse. This commentary reflects on potential explanations for our failure to detect effects of a mailed communication intervention promoting the use of prescription medication take-back boxes among a rural population of adults. This field experiment included adults (Intervention:  = 3,255; Comparison:  = 3,325) in six counties in Mississippi. Pretest and posttest surveys measured use of take-back boxes, intention to use take-back boxes, and Reasoned Action Approach predictors of intention: attitudes, descriptive norms, injunctive norms, and perceived behavioral control. Analyses indicated that the intervention failed to increase participants' intention to use prescription medication take-back boxes. Possible explanations for these null effects include intervention design, low response rates, methodological challenges, and stigma related to the topic area. This commentary provides insights into these explanations and implications for health communication campaigns.