This article examines the rhetorical productivity of ambiguity in the context of a loosely-defined mood disorder formally known as dysthymia, referred to colloquially as mild depression. First, the article offers a rhetorical history of the unusual institutional conditions under which this definitionally ambiguous diagnostic entity was constructed prior to its debut in the DSM-III. Second, the article explores how dysthymia’s definitional ambiguity functions as a rhetorical resource in the context of contemporary online health interactions.

As we enter an era of so-called Do it Yourself health, “patient agency” has become a dominant theme in public discourses of health and medicine. Despite increased salience, patient agency remains a vague term that is capable of being operationalized and moralized in ways that escape attention. To illustrate this, I chart common rhetorical configurations of patient agency in public discourses of health and medicine, and in doing so find that patient agency is commonly rhetoricized as one of three overlapping patient capacities: the capacity to know, the capacity to prevent, and the capacity to decide. Ultimately, I argue that these three rhetorics of patient agency can be deployed to cultivate health subjectivities imbued with untenable ideals of individual control that constrain, rather than open, patients’ rhetorical choices.