Pretreatment attrition and childhood social phobia: Parental concerns about medication.

Pretreatment attrition, the systematic self-exclusion of potential participants during the recruitment phase of a study, poses a significant threat to the external validity of randomized clinical trials. Very little is known about the factors that contribute to pretreatment attrition, especially among families seeking treatment for a child. The current study assessed pretreatment attrition in a randomized clinical trial of behavior therapy, fluoxetine, and placebo for child and adolescent social phobia. Reluctance toward medication treatment accounted for 44.7% of study refusals and was disproportionately common among ethnic minority families. Parents were particularly worried about the potential for side effects or physical/psychological dependency upon the medication. Results are discussed in terms of the implications for external validity in future psychopharmacological clinical trials.