We have read the important article on the premorbid risk markers for chronic fatigue syndrome in the 1958 British birth cohort ^{Reference Clark, Goodwin, Stansfeld, Hotopf and White1} with a lot of interest. The authors reported that parental physical abuse, childhood gastrointestinal symptoms and parental reports of many colds were independently associated with self-reported chronic fatigue syndrome (CFS), after adjusting for psychopathology.

Notably, the authors did not comment on the fact that parental physical abuse, but not sexual abuse, was predictive of CFS, even though childhood sexual abuse is a well-documented risk factor for CFS. More precisely, chronic fatigue was significantly predicted by childhood sexual abuse in a population-based study by Taylor & Jason. ^{Reference Taylor and Jason2} Also, childhood sexual abuse and emotional abuse were most effective in discriminating CFS cases from control individuals in two population-based studies by Heim et al (as well as emotional neglect in one of these studies). ^{Reference Heim, Wagner, Maloney, Papanicolaou, Solomon and Jones3,Reference Heim, Nater, Maloney, Boneva, Jones and Reeves4} A possible reason for this inconsistency is the relatively low frequency of sexual abuse in the study by Clark et al ^{Reference Clark, Goodwin, Stansfeld, Hotopf and White1} (6.3 %), compared with its frequency in the others studies (> 26%). ^{Reference Taylor and Jason2–Reference Heim, Nater, Maloney, Boneva, Jones and Reeves4}

Interestingly, there may be a differential clinical effect according to the subtype of childhood trauma. In the study by Taylor & Jason, ^{Reference Taylor and Jason2} a history of childhood sexual abuse emerged as a significant predictor of post-traumatic stress disorder. Furthermore, significant correlations between scores on a trauma questionnaire and scores for depression, anxiety and post-traumatic stress were observed by Heim et al. ^{Reference Heim, Wagner, Maloney, Papanicolaou, Solomon and Jones3} These correlations remained unchanged when the analysis was restricted to the subscales sexual abuse and emotional neglect.

Recently, our research group examined the impact of childhood trauma in a well-described tertiary sample of patients with CFS. In accordance with the previously mentioned population-based studies, childhood sexual harassment was the best predictor of psychological symptoms in CFS (unpublished data). Taken together, these data emphasise the importance of childhood sexual abuse as a premorbid risk marker for CFS.