As birth rates in high-income countries decline, the Global South will soon be home to the vast majority of the world’s youth and working populations. In fact, according to UNICEF, Africa will have a quarter of the world’s population by 2050. If the majority truly rules, we can no longer ignore the Global South simply by virtue of the sheer size of these populations. Further, if we consider the histories of colonialism, war, financial and resource exploitation, and more that people living in the Global South contend with, there is a compelling argument that mental health research in this region should not only be a priority but a necessity.

It is no longer possible or wise to ignore and exclude the Global South in mental health research efforts if we are to ensure the future of the world.

Since their reported inception in the eighteenth century, longitudinal studies have been used in various disciplines to study change over time. In mental health research, longitudinal studies are an invaluable tool used to understand the mental health needs of people across the globe and inform legislative and treatment decisions. Historically, mental health research has been conducted in high-income countries in the Global North, such as the United Kingdom and the United States of America. Although this research has led to the identification and analysis of trends in mental health in several populations, the focus on Western European groups has produced results that do not necessarily map onto or accurately reflect the experiences of people living in Africa, Asia, or the Middle East.

As part of the Landscaping International Longitudinal Datasets project, we have been searching the world for large longitudinal datasets with the potential to facilitate transformative mental health research. This search is supplying unique insight into the longitudinal data landscape in Africa, Asia, and the Middle East. Whilst countries like China, India and South Africa have large datasets spanning years or even decades, many countries in these regions have few datasets. The lack of longitudinal data is particularly marked in several areas, namely French-speaking countries, countries with small populations, countries in Central and Northern Africa and countries embroiled in armed conflict within the last two decades.

The histories of colonialism, war, resource exploitation, and large-scale inequity perpetrated by internal and external actors vary by locale, culture and region and contribute to several broad reasons for the gap in longitudinal mental health research in the Global South.

These reasons include:

1. A marked focus on communicable diseases such as malaria in these regions. Research and interventions into communicable diseases have not historically lent themselves to longitudinal research. Instead, clinical trials, cross-sectional surveys, and epidemiological studies are the norm.
2. Financial restructuring programs and national debt has meant that many academic institutions in these regions rely on foreign funding and aid to conduct research, leaving the research direction in the hands of outside interests.
3. Historical political instability has often made long-term research difficult as people migrate seeking safety, resources, and opportunity.
4. Research in Africa, Asia and the Middle East is often conducted by researchers and research bodies from the Global North. They directly and indirectly contribute to the delegitimization of research conducted by academics native to these regions.
5. The definitions, symptoms, treatments, and experiences of mental health created and observed in the Global North are not directly comparable to those in the Global South due to culture, experience, language, and other differences.

The reasons above are merely snapshots of the problems in the mental health research space rather than a comprehensive list. What is important is that, despite these challenges, valuable longitudinal data is being collected in Africa, Asia, and the Middle East. The longitudinal datasets that we have found in these regions through our landscaping exercise can be broadly grouped into three groups:

Economic: This group includes living standards surveys, labour market panel surveys, development surveys, microcredit surveys and more. These surveys are designed to follow up on the socioeconomic status of individuals, households, and communities over time. There are several large datasets of this type located in South Africa, Indonesia, Kenya, and the Philippines, to name a few.

Social: These surveys are more focused on demographic information and societal structures. These include family life surveys, mother-baby cohorts, birth cohorts, and ageing studies. China, Japan, South Korea, India, Iran, and South Africa have several datasets of this type with rich data about their participant’s lifestyles, families, and even migratory patterns. The studies in this group are most likely to include measures of mental health and well-being.

Medical or genetic: Datasets of this type tend to focus on a specific disease or condition, an intervention, or an outcome. This may look like a cohort focused on the incidence of malaria, the uptake of anti-retroviral therapy (ART) or the prevalence of short-sightedness (myopia). These surveys usually follow individuals, households or communities collecting biological and medical data through samples, DNA, and hospital records as they monitor health status over time. Biobanks usually collect the genetic and biological data of hundreds of thousands of participants over long periods.

As with most forms of research, the generalisability of the data is critical when analysing longitudinal data. To achieve results that are generalisable and thus suitable for decision-making, large, representative samples are needed. This need has guided the Wellcome Trust in funding Landscaping International Longitudinal Datasets project as a first step in facilitating transformative research that can create a step change in early intervention in mental health for individuals across the world. Longitudinal population studies are vital to improving our understanding of the mental health of populations in Africa, Asia, and the Middle East. The focus on diverse populations is why we are landscaping the entire world rather than the few countries that have historically led the field of longitudinal research.

Several studies were suggested to the landscaping team by members of the public via our email landscaping-wellcome@kcl.ac.uk or via our website form at landscaping-longitudinal-research.com. Submissions make sure that the landscaping team does not miss any datasets that have potential for transformative mental health research. With your help, we can ensure that no stone is left unturned and that all populations, especially in the Global South, are represented in our data.

Help us in our goal of finding datasets in every corner of the world as improving our knowledge of the mental health needs of people in Africa, Asia and the Middle East is essential as people in these regions deserve to have their mental health needs met.