Risk assessment has become a large and anxiety-provoking part of the work of many psychiatrists. This article unpicks the different meanings of the word ‘risk’ to seek out the source of that anxiety, looking at both statistical and sociological ideas about risk. A risk assessment is often a subjective, plastic and context-dependent statement about a patient that carries strong moral overtones. Risk management is also highly anxiogenic for those charged with carrying it out, because uncertainty about the future is impossible to eliminate and the consequences of an adverse outcome in the patient may also carry hazards to the doctor making the risk assessment. This leads to behaviour change in people carrying out risk assessments as they attempt to minimise their anxiety in a rationally selfish way, often with unintended negative consequences for patients, doctors and health service providers generally. Some possible strategies for minimising this effect are considered.