A second concern is the retrospective reporting of both PTEs and lifetime drug use. While the potential for recall bias is reduced in younger participants with shorter lags between timing of event and reporting of event,20-22 we still cannot rule out the possibility of under-reporting of drug use due to social desirability bias and under-reporting of PTEs due to forgetting or trauma-related non-acceptance. These biases could result in either over-estimation or underestimation of results reported here. However, the prevalence of drug use reported in the NCS-A is consistent with or higher than that reported in other surveys,50,61,62 and the prevalence of any exposure to PTEs is only slightly lower than that of adult samples,44,63 suggesting that under-reporting may not be of great concern in this study.
