Abuse and ACTH Response to Corticotropin-Releasing Factor

To the Editor: Dr. Heim et al. reported that adult survivors of childhood abuse may have altered pituitary-adrenal axis response to provocative challenge tests. These authors found that nondepressed, formerly abused women exhibited a significantly greater ACTH response to CRF stimulation than comparison women, but it seems possible that the differences observed might be entirely due to differences in the ethnic composition of the study groups.

Specifically, as Dr. Heim and colleagues correctly noted, African American individuals showed about twice as much ACTH response to CRF administration as Caucasians. If we assume that the nonwhite subjects in this Atlanta-based study were all African American, then 55% of the abused women without depression were African American, as opposed to only 25% of the comparison women and 15% of the women in the two depressed groups. These ethnic ratios could therefore account almost perfectly for the differences in ACTH response shown in the authors’ Figure 1 without reflecting any effect of depression or history of abuse. The authors themselves noted that there was a highly significant race-by-time interaction in their analyses. Therefore, I think the authors would have been obliged to report the results separately by race (and perhaps by education) since Dunn’s multiple comparison procedure might not have been sufficient for analysis in this instance. It would be helpful if the authors would clarify this issue and, in particular, provide summary data for findings among the various groups broken down by race (and perhaps by education).