This article examines an explanation circulating within a U.S. multidisciplinary pediatric pain clinic that links the neurobiology of functional pain disorders to desirable personal attributes such as smartness and creativity. Drawing on ethnographic observations and the analysis of video-recorded clinical interactions and focusing on two cases, I introduce the term personhood diagnostics to explore how the explanatory framework worked not only to pinpoint a pathophysiological mechanism for pain to legitimize it as “real” but also to cast patients as virtuous persons. In doing so, it laid the groundwork for an ethic of clinical care that privileged the patient’s responsibility for treatment. Within this narrative logic, diagnostic explanations reveal not only causal pathways but also predictive claims about recovery. By considering what is at stake when personal attributes are marshaled within a neurobiological diagnostic register that also lays out the patient’s role in healing, this article complicates psychosomatic accounts of pain.