Response to Commentary on Everly et al. (2016).

W e appreciate the great interest that the commentators had in reading our article, “The potential efficacy of psychological first aid on self-reported anxiety and mood” (Everly et al., 2016). We further understand the importance of making contributions to a unique field wherein major international health organizations have taken the unusual stance of supporting the use of psychological first aid (PFA) in advance of the emergence of supportive clinical trials (see Everly and Lating, 2017, for a review). We recognize and respect that a field advances from good discourse, and we agree with the commentators when they “urgently call for more research in the area, either in a more controlled laboratory setting or in a field situation. ” This was clearly the intent and stated purpose of our pilot study. The primary contention raised by the commentators is that we did not report the statistical between group comparisons for the PFA condition and social acknowledgment condition at the three designated time references (i.e., baseline, end of disclosure, and 30-minute after disclosure) used in the study. The commentators correctly note that the statistical comparisons between the PFA group and the social acknowledgment group on the State-Trait Anxiety Inventory (STAI; Spielberger et al., 1970) at these three time points did not yield statistically significant results. We aptly acknowledged this in our article as well. However, and as alluded to in the original article, we suggested that the withingroup differences were what we considered to be worthy of further exploration. As seen in Figure 1, which was not included in the original brief report, assessing the within-group differences, which are more sensitive to clinically relevant change, have less error variance, and do not create an “average” participant, but rather uses each participant as his or her own control, resonated with us regarding the potential clinical implications of PFA. This contention is supported by the work of Tennen et al. (2000) and Lazarus (2000), who cogently argue that within-subject designs are more appropriate than between-subject designs for the analysis of stress and coping-related behaviors. As reported in the original analysis, the PFA group, using awithin-subjects t-test showed that that the PFA group reported significantly lower levels of anxiety at 30 minutes after disclosure in comparison to their baseline levels of anxiety ( p < 0.003, d = 0.82, 95% confidence interval [CI] = 0.34–1.31), whereas this significant change in scores did not occur in the social acknowledgement group; in fact, their mean scores at 30 minutes after disclosurewere higher, albeit not statistically than their mean baseline scores ( p = 0.333, d = −0.21, 95% CI = −0.64 to 0.23). In light of Figure 1, which shows that the PFA group appears to drop below baseline at 30 minutes after disclosure and that the social acknowledgement groups does not drop below baseline at 30 minutes after disclosure, we decided to conduct a between-groups comparison using the participants' paired difference scores (30 minutes after disclosure minus baseline disclosure), which incorporates a control for individual differences and thus provides greater sensitivity to capture a difference between the two groups. To determine if the change from baseline anxiety to 30 minutes after disclosure was statistically different between the PFA and the social acknowledgement group, a t-test analysis was conducted. Comparing the difference scores (30 minutes after disclosure minus baseline disclosure) between the two groups revealed that the change score mean (using paired scores for each participant) for the PFA group (mean = −3.95, SD = 4.79) was indeed statistically different from the change score mean for the social acknowledgement group (mean = 1.17, SD = 5.99), t(40) = −3.12, p < 0.004, d = −0.97, 95% CI = −0.32 to −1.60). It should be noted that the effect size of d = −0.97 is considered to be a large effect. Therefore, although the two groups did not reveal statistical differences (nor should they have at baseline and at 30 minutes after disclosure) using a between-groups analyses at each measurement period (baseline: t[40] = 0.54, p = 0.591; postdisclosure: t[40] = −0.61, p = 0.543; 30-minute postdisclosure: t[40] = −1.27, p = 0.211), the changes over time between 30 minutes after disclosure and baseline disclosure (within-group change) that occurred between the two groups reflect a statistically significant difference. Furthermore, a post hoc power analysis examining the effect size for the 30-minute