The iatrogenic power of labeling medically unexplained symptoms: A critical review and meta-analysis of “diagnosis threat” in mild head injury

Authors have claimed that exposing individuals who report ambiguous symptoms with diagnostic labels may have an iatrogenic (i.e., harmful) effect. Experimental studies on what has been dubbed diagnosis threat have, indeed, documented impairments on cognitive performance tests and symptom self-reports among individuals whose attention has been called to such labels and their connotations. What is the clinical potential of these laboratory observations? To address this issue, we conducted a review and meta-analysis of published diagnosis threat studies. All these studies relied on individuals reporting a mild head injury in their history (k = 6 data sets; N = 309), a diagnosis known to be accompanied by lingering medically unexplainable symptoms in a subset of individuals. The obtained weighted effect size was modest (d = 0.19, 95% confidence interval [-0.04, 0.41]), with a more pronounced effect on cognitive measures (d = 0.25) than on symptom self-reports (d = -0.05). Taken together, our findings indicate that strong claims about the harmful potential of diagnostic labels may need to be reconsidered. We conclude this article with a recommendation for future research on iatrogenic clinical practices surrounding medically unexplained symptoms. Namely, to go beyond the study of diagnostic labels and systematically target additional sources that may encourage and maintain nonadaptive illness behavior in patients, including the use of premature interventions, excessive diagnostic testing, (intentional) symptom exaggeration, and the presence of secondary motives.