The DSM and ICD diagnostic systems have developed largely in response to clinical interests, though they are used for other purposes as well. Careful attention is also needed to consider the balance of ethical and commercial interests. Public health aims of representing the burden of disease and disorder help to mobilise resources globally, nationally and locally; and relevant diagnostics and assessments guide services and programmes for the mental health of patients and populations. Like other areas of public health, the scope of community mental health extends beyond the treatment orientation of clinical services and community psychiatry. Priorities also include reducing vulnerability to prevent mental health problems and enhancing resilience to promote mental health. As the next wave proceeds in revising our psychiatric systems of classification, advancing such an agenda will help ensure that efforts to achieve the mental health of populations are effective, as they become more responsive to current developments in public health-which have recently been characterised with reference to four revolutions.