In The Lancet Psychiatry, psychiatrists Ilina Singh and Simon Wessely discuss the current, controversial state of understanding of ADHD, and ask whether finding a biomarker for ADHD would actually be a good thing if it happened.
“One way of answering this question is to see psychiatry as an essentially vulnerable science, poised as it is on the boundaries of medicine, mind, and society,” the authors write. “On this contested ground, psychiatry has only imprecise methods to provide proof that its medical description of what is going on with a child is the right description. In this sense, psychiatry is continuously battling diagnostic uncertainty. In many other disease categories, but in by no means all, validated biological markers — biomarkers — can inform diagnosis and authorise the medical account of disease. These biomarkers can also be problematic — there are false positives in cancer and shifting thresholds in heart disease. But ideally, biomarkers in these specialties provide some account of what is going on under the skin, enabling better predictive algorithms and treatment strategies. Psychiatry has yet to discover, let alone use, well established biomarkers in diagnosis and treatment—or when it does, as for example in the case of neurosyphilis, the problem suddenly ceases to be psychiatric.”
Yet would biomarkers indicating the definitive presence of an actual “ADHD” disorder truly help anyone? Perhaps not, suggest the authors. “It is also worth considering that biomarkers do not resolve the ethical concern about the diagnosis of ADHD as a violation of childhood: should this particular set of childhood behaviours or capacities be labelled a medical disorder requiring observation or intervention? This aspect of the problem of diagnostic uncertainty in ADHD is not about whether or not the diagnosis is correct; it is more fundamentally about whether or not medical diagnosis is the right thing to do. From this perspective, biomarker evidence might contribute to better (that is, more accurate) diagnosis of ADHD, but clinicians might also get better at doing the wrong thing.”
Singh, Ilina, and Simon Wessely. “Childhood: A Suitable Case for Treatment?” The Lancet Psychiatry, June 2015. doi:10.1016/S2215-0366(15)00106-6. (Full text with registration)