Aim – to provide a conceptual and practical analysis of the impacts of mental health diagnoses on consumers and to consider how service users might contribute to the new psychiatric classifications currently being drawn up. Methods – A search was carried out revealing a very sparse literature on this topic. Consultations with service users were conducted and the views of experts sought. Results – Diagnosis is important as it marks the formal status of psychiatric patient being conferred. Consumers react differently, and often, negatively to this. Stigma can follow from a diagnosis. The process of giving a diagnosis can range from one of negotiation and taking the person's strengths into account to the blunt allocation of an unwanted label. Consumers can be reduced to their diagnosis so it becomes their whole personhood and this can have an effect on their sense of self. However, consumers are not passive victims and have their own strategies for dealing with these issues. Conclusion – Consumers can use these experiences to make contributions to the new diagnostic classification systems and to future research.