This article discusses sceptical arguments about measurement scales. Measurement scales are part of a promising agenda of openness, transparency and patient and public involvement (PPI) in medical research, but have received critical, sometimes hostile attention from anthropologists. This is because scales repackage localised cultural assumptions about distress as something universal and pan-human and have the capacity to reshape people's interior lives in unhelpful, possibly harmful ways. We take as an example the Patient Health Questionnaire-9 (PHQ-9). Use of the PHQ-9 is currently mandated by major funders. But its history suggests flawed PPI and a lack of openness. The article suggests a constructive role for anthropology in mental health research, using ethnographic evidence and theory to show how, although they have their uses, mental health scales should not be regarded as inert or harmless.