A significant portion of the scholarship in analytic philosophy of psychiatry has been devoted to the problem of what kind of kind psychiatric disorders are. Efforts have included descriptive projects, which aim to identify what psychiatrists in fact refer to when they diagnose, and prescriptive ones, which argue over that to which diagnostic categories should refer. In other words, philosophers have occupied themselves with what I call “diagnostic kinds”. However, the pride of place traditionally given to diagnostic kinds in psychiatric research has recently come under attack, most notably by a recent initiative of the National Institute of Mental Health, the Research Domain Criteria Project, that seeks to exclude diagnostic categories from experimental designs and focus on other sorts of psychiatric kinds. I argue that philosophical accounts privileging diagnostic kinds must respond to this new line of criticism, and conclude that philosophers need to either counter psychiatrists’ growing suspicion about the hegemony of diagnostic categories in the clinic and the laboratory, or join in redirecting their efforts toward the development of robust accounts of other sorts of psychiatric objects and processes.