Diabetes mellitus is a complex metabolic disorder characterised by persistent hyperglycaemia. The prevalence of diabetes is increased in people with schizophrenia.

To provide an update of current thinking in diabetes for practising psychiatrists.

Literature review.

Diabetes is a costly condition in individual, social and economic terms, and the global burden of diabetes is increasing in most populations. The insidious onset and asymptomatic nature of diabetes results in many people remaining undiagnosed and at great risk of developing life-threatening vascular complications. Lifestyle and pharmacological interventions can reduce incident diabetes and delay its progression.

Public health policies are urgently required to encourage people to follow a healthy lifestyle. Primary prevention strategies for diabetes should target individuals at especially high risk of developing type 2 diabetes, including those with severe mental illness.

Although postnatal depression is a common condition, with adverse effects on the child, mother and partner, there has been no research to date linking analyses of its origins and consequences with studies of service provision in different national health and social systems.

The Transcultural Study of Postnatal Depression (TCS–ND)was setup to develop a set of instruments to facilitate such research.

Seven research instruments were piloted in studies carried out in ten centres in eight countries. A qualitative study looked at the cross-cultural equivalence of the concept of postnatal depression.

The results are reported in the individual papers in this supplement.

Reliable and culturally valid measures are now available for future comparative research into postnatal depression within different health systems and countries.

Postnatal depression seems to be a universal condition with similar rates in different countries. However, anthropologists question the cross-cultural equivalence of depression, particularly at a life stage so influenced by cultural factors.

To develop a qualitative method to explore whether postnatal depression is universally recognised, attributed and described and to enquire into people's perceptions of remedies and services for morbid states of unhappiness within the context of local services.

The study took place in 15 centres in 11 countries and drew on three groups of informants: focus groups with new mothers, interview swith fathers and grandmothers, and interviews with health professionals. Textual analysis of these three groups was conducted separately in each centre and emergent themes compared across centres.

All centres described morbid unhappiness after childbirth comparable to postnatal depression but not all saw this as an illness remediable by health interventions.

Although the findings of this study support the universality of a morbid state of unhappiness following childbirth, they also support concerns about the cross-cultural equivalence of postnatal depression as an illness requiring the intervention of health professionals; this has implications for future research.