Most people know nothing about quantum mechanics or how a microwave oven works. Generally however, people don’t express strong opinions on either of these topics, which probably saves lots of pointless, frustrating conversations for people who did physics at Uni. The same is not true regarding Whiplash. It seems ownership of a car and/or a neck qualifies one for a strongly-held belief regarding the how, the who, the why and the what-I’d-do-if-it-were-up-to-me.
To be fair, it is a perplexing condition; peoples’ symptoms follow variable courses, the scientific literature reveals divides in the thinking of researchers, opinions among clinicians vary, the popular media has a go, insurance companies have a particular interest and regulatory authorities can also become involved. In the interests of adding some data from a real, live, apparently well-conducted study I’d like to highlight something recently published in Spine which looks to undress some of the issues surrounding Whiplash.
As a little bit of background, previous studies have reported an association between whiplash injuries and psychological variables, the prevailing hypothesis being that the pain and symptoms associated with the physical injury result in psychological distress. This particular study used a large ongoing population survey in Norway to look at whether levels of anxiety and depression at one point in time predict whether or not someone is likely to report a Whiplash injury in the 11 years that followed. This is interesting because it really gives us a chance to get at the chicken or egg question. After controlling for age, gender and alcohol-problems they found that higher levels on their depression and anxiety measure do in fact increase the likelihood that a person will report a whiplash injury down the track (Odds Ratio 1.6).
In their interpretation, the authors discuss several slightly, but importantly, different ways of accounting for their findings. Most significantly they cannot say whether previous anxiety/depression level makes it more likely that someone will actually have a whiplash injury or whether it makes them likely to attribute neck symptoms to whiplash (significant, given that estimates of 12-month prevalence of non-specific neck pain run somewhere around the 30% mark). They also point out that they cannot exclude the possibility of bidirectional causality and that there may be confounding factors that were not adjusted for at baseline.
Taking care to note that the only thing I know about my microwave is that it makes last-night’s pizza taste better, it seems to me that these findings might nestle quite nicely amongst some of the interests of those frequenting this forum. The interaction between psychological state and symptoms might fall into the domain of central sensitivity, alternately (or perhaps complementary) maybe the interaction between psychological traits and cognitive appraisal is a factor here. What if we were to take this one step further though? We are pretty comfortable with the idea of some people being more susceptible to certain health conditions e.g. cancer, schizophrenia, addiction, Alzheimer’s – but what about musculoskeletal conditions?
Over to you neuroscientists and clinicians!
Before I go, here is a list of some of the things this study isn’t saying: Whiplash doesn’t involve some kind of physical/anatomical trauma, people with whiplash injuries are just depressed/anxious, whiplash injury symptoms are just in the head, people with whiplash injuries having nothing wrong with them, people with whiplash injuries are motivated by compensation and there would be no whiplash if it weren’t compensated…(have I missed any?)
About Steve Kamper
Having completed Physiotherapy at USyd and a PhD at the George Institute in Sydney, Steve is currently “working” in Amsterdam at the EMGO+ Institute on an NHMRC fellowship. The thing Steve likes most about being funded by a government fellowship are the endless opportunities to remind mates that they are, in fact paying for every beer he has. Work involves research into the influence of patient expectations on outcome, back and neck pain, outcome measurement and the ongoing search for European conferences to ensure all holidays are tax deductible. Steve likes to spend his spare-time running around next to canals, riding his bike, giving blank looks to people who ask questions in Dutch and making sure he gets at least twice the recommended daily dose of ICECReam (www.theicecream.org/).
Reference
Mykletun A, Glozier N, Wenzel HG, Overland S, Harvey SB, Wessely S, & Hotopf M (2011). Reverse Causality in the Association Between Whiplash and Symptoms of Anxiety and Depression: The HUNT Study. Spine, 36 (17), 1380-6 PMID: 21217426