I read with interest the systematic review of pharmacotherapy for post-traumatic stress disorder (PTSD) by Mathew Hoskins and colleagues. Looking at Fig. 2 of the paper and at the online-only supplemental file, however, it seems to me that two unpublished studies have been counted twice in the meta-analysis. As far as I can see from the information reported in the review, the study ‘Eli Lilly’ is the same as ‘Martenyi 2007’ and ‘Pfizer 589’ is the same as ‘Friedman 2007’ (same drugs, same comparisons, same sample size). I would be grateful if the authors could clarify the matter.