UK "Psychiatric Survivors"-a variety of activist groups comprising individuals who have been on the "receiving end" of psychiatric treatment-have, since the mid-1980s, mounted a challenge to the psychiatric system. "Survivors" have formulated their own knowledge-base concerning a range of human problems hitherto regarded as the province of "official" psychiatry only. "Official" knowledge stresses scientific classification, professional expertise, and statistical evidence: "Survivor" knowledge, by contrast, emphasises individual experience, the traumas of the life-course, and the personal testimony of the survivor as itself expert data. This paper focuses upon the truth-claims enacted by the "testimony of the survivor" and the relation of "testimony" to political practice. Specifically, I analyse a key text containing the testimonies of female survivors whose behaviour has been officially labelled as "deliberate self-harm"; that is, women who harm themselves, through self-poisoning or self-laceration, and subsequently receive medical/psychiatric treatment. The main focus is upon the political functions of testimony in theory and practice-the ways in which "survivors" challenge the power of psychiatry.