Although the effort in the study by Mayou & Bryant (Reference Mayou and Bryant2002) is substantial, we find that there is a tendency in such studies to fail to account for at least two important confounding variables. Our own experience, in both clinical and medico-legal practice, is that asking patients about pre-accident emotional stress is too often unreliable. Interviews with family members and review of employment records and reports often uncovers a wealth of data on these patients that was otherwise not forthcoming. Yet this is a difficult task in research studies in most cases. What is less difficult, however, is seeking the opportunity to review all pre-accident medical records, which often refer to lengthy or recent histories of significant life stressors. This is important; if some of the subjects who reported a lack of pre-accident emotional difficulties in a study actually have them, they confound the comparison of emotionally vulnerable v. non-vulnerable accident victims. No difference will appear to exist between the two groups because in reality they are much more alike than the researchers can know. Although researchers do use methods that suggest self-reported data is still valid, if the purpose of the research is to study psychosocial variables, then short-cuts or surrogate measures are not sufficient.

Also, post-accident stressors unrelated to an accident (e.g. death of a friend or family member, or moving house) have been shown, albeit in a small group of subjects, to be important predictors of whiplash outcome (Reference Karlsborg, Smed and JespersenKarlsborg et al, 1997). In research, to obtain this information, one need merely ask the subjects to check off what may seem like a list of not uncommon life events. We have found in clinical and medico-legal practice that patients tend to be more forth-right about reporting these events, although we are impressed at how frequently people manage to cope and keep working after many stressful life events, and yet have work disability and develop post-traumatic stress disorder after minor motor vehicle collisions. Perhaps it is as Sir John Collie remarked long ago: