Response to: "Updated and rectified meta-analysis shows no effect of propranolol versus placebo on traumatic memory reconsolidation disruption".

Abstract

In their letter to the editor, Steenen and colleagues1 argue that the conclusions of our meta-analysis2 on the clinical efficacy of reconsolidation impairment using propranolol are “incorrect in the context of (...) psychotrauma-related symptomatology.” They claim that we did not assess risk of bias and critique our omission of 3 unpublished studies (Aikins,3 Saladin,4 and Orr5). We are not convinced by their attempt to rectify our analysis. Although this is a matter of debate,6 we were asked during the JPN peer review of our manuscript to omit unpublished data from our meta-analysis because the methodological quality of such studies is difficult to verify. Indeed, we could not verify important methodological information with respect to the unpublished results (n = 6) of Aikins,3 such as the adequacy of blinding methods. Moreover, we verified methodological information in the study by Orr5 with the author himself and concluded that the data from this pre-emptively terminated (rather than unpublished) study with n = 5 randomized participants were not suitable for meta-analytic purposes. The inclusion of studies with very small samples in a meta-analysis (n ≤ 3 per group) is bound to compromise the precision of the overall effect estimate.6 We also could not verify important information such as the outcomes used to compute the effect size for Saladin’s unpublished study of reconsolidation interference in participants with posttraumatic stress disorder (PTSD) and comorbid alcohol dependence.4 Considering that Steenen and colleagues1 argue against including studies of addiction (but see Gisquet-Verrier and colleagues7), it is unclear why they included Saladin’s study in their analysis. But even more problematic, we found