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A world-first longitudinal study on depression

Academics at the University of KwaZulu-Natal (UKZN), and their peers from the US and the UK, undertook a study of the spatial structuring of depression on a national scale in SA. This longitudinal study, a world first, was recently published in the prestigious scientific journal, Nature Scientific Reports.

The study was called: "Spatial Structure of Depression in SA: A Longitudinal Panel Survey of a Nationally Representative Sample of Households". It analysed the spatial distribution of depression in SA.

Depression is a common illness worldwide, with an estimated 300 million people affected. In SA, an estimated 9.8% of the adult population experiences major clinical depression. Despite treatment being available, only a quarter of the estimated 9.8% have sought treatment and care for a mental disorder.

This study identified unusual clusters of depression cases across SA using a nationally representative cohort of individuals who were free from depression at the start of the study.

The identification of spatial clustering of new cases enables an understanding of the individual's exposure to external factors within these clusters. One of the findings of this study was the overlap in spatial distribution between high levels of tuberculosis (TB) and depression.

It is important to note that within these geographical clusters, there already exists a high burden of TB and HIV-TB co-infection.

From 2008 to 2012, a total of 14 097 existing cases of depression were reported. A spatial scan indicated 14 significant clusters of depression. Most of these clusters were located in the northern and eastern parts of the country in the North West, Free State, Eastern Cape and KwaZulu-Natal provinces.

The 14 clusters covered only 19.7% of SA's total area, but contained 34.7% of reported cases of depression.

Professor Jonathan Burns, an honorary professor of psychiatry at both the UKZN and the University of Exeter, UK, said: "The stress and physical deterioration caused by diseases such HIV and TB have large impacts on the mental health of an individual. Social discrimination and stigma, stress, the constant need for healthcare, the potential lack of family support and the response to medications are among the factors that could drive the high rates of depression among people with HIV/TB."

Further analysis of the data indicated that the largest racial group was black African, with the majority being women, single parents and the unemployed. Communities found in the clusters were poorer, less educated people living in traditional rural communities, adding to their burden of inequality as well as the challenge of social development.

The study has identified communities where there are unusually high numbers of new cases of depression. This will assist policymakers to implement measures that are tailored to the needs of a particular community.

Authors of the study included UKZN professors Frank Tanser and Rob Slotow, who are both affiliated to the University College London; Dr Andrew Tomita and Dr Alain Vandormael from the UKZN and the KwaZulu-Natal Research Innovation and Sequencing Platform; Professor Diego F Cuadros from the University of Cincinnati, US; and Professor Jonathan Burns.

Words: MaryAnn Francis