مرحباً بكم في الأمم المتحدة 
Man-provoked incidents are rapidly spreading to new corners of the globe. Between April and May of 2024, the state of Rio Grande do Sul, in southern Brazil, was ravaged by torrential rainfall and unprecedented flooding, resulting in hundreds of deaths and leaving hundreds of thousands unsheltered or in extreme vulnerability. This catastrophic climatic event is thought to be linked to the exacerbation of El Niño—the natural warming of ocean waters in the South Pacific—intensified by fossil fuel burning and global warming. Amid the cataclysm, a group of mental health providers united to assist the grieving and newly houseless community with volunteer psychological and psychiatric emergency aid.
This collective effort highlights a new—and even bleaker—facet of climate change: how it leads to abrupt and traumatic loss (whether of life or property, individual or collective and all types of bereavement) and its short- and long-term effects on human mental health. Beyond the intricate and direct interconnectedness between geopolitical factors and mental health, the situation exemplifies one of many calls to action for mental health professionals, governmental representatives, and the global community to consider improving mental health as a central catalyst for the urgent pursuit of a sustainable future, which requires systemic balance in environmental, economic, and sociopolitical spheres.
An initial analysis of this issue raises the question of what kind of future we, as a society, are shaping. A quick review of the last 300 years of world history reveals a stark disparity: humanity has rapidly advanced its ability to optimize hard and soft technologies, while simultaneously diminishing its commitment to preserving the world as we know it—a place where diverse living and inanimate beings coexist harmoniously, and where peoples harbour their own ethnic, social, moral, political, and economic differences, whether inter- or intra-community. In simple terms, we still face the challenge of distributing wealth equitably and successfully converting wealth into well-being. In this context, the United Nations (UN) developed—and officially endorsed during the 2015 Sustainable Development Summit—a series of desirable achievements that would serve as a blueprint for multilateral policymaking, targeting the next one and a half decades.
The establishment of the 2030 Agenda, comprised of 17 Sustainable Development Goals (SDGs), marked a turning point in the collective pursuit of a better future—one that balances economic growth, social progress, and ecological safety, as defined by the core concept of sustainability. Specifically, the SDGs include both concrete goals—such as "Zero Hunger," "Affordable and Clean Energy," and the conservation of "Life on Land" and "Life Below Water"—and more abstract aims, such as the pursuit of "Peace, Justice, and Strong Institutions" and "Sustainable Cities and Communities." Despite being labeled by some as fanciful and idealistic, the world has already demonstrated the feasibility of collective global effort in pursuit of a greater good.
In the early 2000s, the UN’s Millennium Summit set eight specific goals, including the eradication of poverty, combating HIV/AIDS and other communicable diseases, and improving maternal and child health, to be achieved by 2015. The world witnessed unprecedented progress in the first 15 years of the 21st century, including the largest reduction in poverty in recent decades (with the number of people living in extreme poverty cut by more than half), a 40% decrease in new HIV infections, and the democratization of antiretroviral therapy, which saved 7.6 million lives, as well as significant improvements in maternal and child health, as documented in the Millennium Development Goals Report. While acknowledging the uneven distribution of successes and challenges in some areas, the data and analysis in the report demonstrate that "with targeted interventions, sound strategies, adequate resources, and political will, even the poorest countries can make dramatic and unprecedented progress". This leaves the 17 SDGs as a beacon of both intentional and practical hope for the 2015-2030 period.
Along with the pondering of hopes and fears regarding the future of the globalized world, one component is gradually making its way to the center of public discourse: mental health. Although sometimes viewed as a primary target for intervention, a strong body of evidence shows that the correlation between mental health and sociodemographic factors goes much deeper than a unilateral flow of causality. Conducting a deductive reasoning process, aligned with the modern holistic definition of health as "a state of complete physical, mental, and social well-being, and not merely the absence of disease or infirmity", it is plausible to conclude that social inequality is linked to unsatisfactory mental health outcomes—particularly when considering the infringement or absence of basic human rights. For instance, traditional biomedical thinking often associates food insecurity with nutritional deficiency, hindering physical development, increasing susceptibility to infectious diseases, and other physical conditions.
What is often overlooked in this framework is how hunger acts as a disruptive stressor to the individual and collective psyche. In the 1950s, the Brazilian physician and thinker Josué de Castro drew international attention by opposing neo-Malthusian currents that viewed hunger as a natural consequence of population growth—rooted in prejudiced determinist undertones—and theorizing that famine is, instead, an anthropogenic issue rooted in sociodemographic determinants and fundamentally an aggression against the human body and mind. Castro's pioneering ideas for the time earned him multiple Nobel Peace Prize nominations and famously influenced concepts like the Biopsychosocial model proposed by George L. Engel in 1977, serving as a guiding principle for global multilateral efforts toward food security as a gesture of respect for humanity and human rights. Furthermore, his paradigm shift and legacy have evolved into some of the modern axioms of public health, social inequality, sustainability, and their correlation with mental health, supported by growing evidence of a significant association between food insecurity and not only psychological distress but also PTSD and common mental health disorders (including anxiety, depression, and somatoform disorders) in Afghanistan, India, South Africa, Guatemala, and Mexico.
Expanding on the example of hunger, it is crucial to emphasize that other important sociodemographic factors interact multidimensionally to impact mental health, leading to an uneven distribution across different regions of the world and sectors of society. A priori, it is known that mental disorders and socioeconomic status function in a bipartite, self-reinforcing cycle: mental disorders lead to reduced income and employment, which perpetuates poverty and, in turn, increases the risk of mental disorders. Supporting this, a systematic review of 115 studies conducted by Lund and collaborators found robust epidemiological evidence that various dimensions of poverty and lack of social assistance are positively associated with mental disorders, with varying degrees of significance, particularly in low- and middle-income countries (LMICs). On the other hand, Castadelli-Maia and Bhugra’s 2022 epidemiological study revealed a gradient in the distribution of prevalence across countries: high-income countries reported higher levels of mental and substance use disorders; there were no significant differences in the prevalence of conduct and depressive disorders between low- and high-income countries; and higher prevalence of intellectual disability was found in low-income countries. Among the many interpretations made possible by this data—such as the link between low education levels and intellectual disability—this discussion highlights two main issues: 1) the existence of socially disadvantaged people even in high-income countries; and 2) the unequal access to mental health services.
Firstly, one important social phenomenon to recognize is that, in wealthier parts of the world, the impoverished, indebted, unemployed, less educated, and socially isolated segments of the population tend to suffer more severely from psychiatric disorders and their associated difficulties, as evidenced by large surveys conducted primarily in Europe. For example, in the 1991–92 UK British Household Panel Survey, when comparing household income by quintiles, the middle three-fifths had more General Health Questionnaire 12 (GHQ-12, a validated screening tool for common mental health disorders) ‘positives’ (scores of 3 or more), OR 1.16 (1.0–1.34), and the lowest fifth had far more GHQ-12 ‘positives,’ OR 1.45 (1.21–1.74), than the highest fifth. Secondly, but equally important, as mentioned earlier, access to mental health services can be examined as one of the key challenges in improving mental health globally.
Despite being better documented in wealthy countries, it is not yet fully understood whether lower rates of mental disorders in low-income countries arise from a genuinely lower real-life prevalence or from limited diagnosis, support, and reporting of epidemiological data. As noted by the 2019 Global Burden of Disease (GBD): "Disability-adjusted life years rates for mental disorders were high in many high-income countries and were lowest in parts of sub-Saharan Africa and Asia, where the coverage of epidemiological data was lowest, and therefore there is more uncertainty surrounding estimates". The urgency of addressing this uncertainty becomes even more apparent when considering that, despite 1 in every 10 people worldwide having a psychiatric condition, only 1% of the health workforce is qualified to meet mental health demands, according to the World Health Organization. These studies and statistics, more than just exemplifying a trend, result from rightly subjecting mental health to the prism of Dahlgren and Whitehead's Social Determinants of Health (SDH) theory, which serves as a key tool in addressing what may be this century's biggest public health challenge.
However, the social determinants model has proven insufficient in fully explaining or guiding interventions for how different collective factors influence mental health. More recently, the scientific community has proposed expanding Dahlgren and Whitehead's framework to include geopolitical determinants of health. In particular, within the realm of mental health, there is increasing emphasis on factors such as climate change, human actions, migration, legal status, minority stress, ethnocultural identity, gender equality, politics, and economics, among others. These factors complement the more proximal determinants, such as income, employment, and housing, in the previously dominant model. While the precise dynamics of these factors are not yet fully established, it is suggested that environmental factors directly harm brain health. This is evidenced by the association of solvents, particulate matter, and other air pollutants with an increased risk, in order of significance, of dementia/cognitive impairment, postpartum depression, and schizophrenia relapse. Additionally, rising temperatures have been linked to adverse mental health outcomes such as suicidal behavior (RR=1.012 per 1°C increase; 95% CI: 1.011-1.014) and mental disorder-related mortality (RR=1.024 per 1°C increase; 95% CI: 1.015-1.033), as reviewed by Radua and collaborators earlier this year, based on a sample size of hundreds of millions (8). The indirect effects of climate change and natural disasters as sources of psychological distress are equally undeniable, bringing attention to the concept of eco-anxiety, defined by the American Psychological Association (APA) as "the chronic fear of environmental catastrophe resulting from observing the seemingly irreversible impact of climate change and the associated concern for one's future and that of future generations." Another significant source of distress in the globalized world is migration, which is entangled in a cycle of poverty, stigmatization, and violence that begins before displacement and often continues in the new settlement, culminating in acculturation, solastalgia, depression, anxiety, and trauma disorders. The unequal distribution of such sociopolitical and environmental phenomena should not be overlooked. For example, the Global South is disproportionately affected by climate change compared to Northern Hemisphere countries, and North African and Middle Eastern nations experience higher rates of emigration and forced displacement.
The evidence and arguments presented in this essay solidify the importance of addressing mental health as a critical component of sustainable development—either as a driving force behind the urgency for action or as a verifiable indicator of sustainability and balanced social and environmental progress. To achieve this, it is crucial for the international community to work together through public health policies that address both mental health and sustainable development interchangeably. For instance, as previously discussed, adhering to the United Nations' 2030 Agenda—embodied by the 17 SDGs—should be seen not as an idealistic pursuit of a utopian "better world," but as a concerted effort to actively follow a set of systematic predefined actions, guidelines, and attitudes that lead the global community toward a future that better accommodates people's needs and well-being while ensuring basic human rights, thus improving mental health on a global scale. It would be particularly useful to include mental health assessments in initiatives such as promoting better nutritional support in insecure communities, with the goal of documenting and evaluating the strategy's impact on mental health, reducing the burden on health services and costs, and integrating mental health as a cost-benefit measure and target into development programs.
As stated throughout this essay, improving mental health is also complicated by the disparities in access to mental health services and the workforce's capacity to deliver diagnosis, treatment, and psychosocial support across different regions and among different population groups. This issue calls for the expansion and improvement of the mental health workforce through increased educational opportunities and adequate training, particularly for aid in settings affected by climate change and humanitarian crises. To further harmonize public discourse, psychiatrists, psychologists, and mental health providers should act as advocates not only for the expansion of mental health interventions but also for the inclusion of mental health outcomes in developmental, social, and ecological policymaking. Together, these programmatic actions, along with the strengthening of individual interventions, should be considered top priorities for the global community, forming a "love letter" to the minds we harbour and nourish and to the world we share.
By Victor Santana, Winner of the 2024 WPA Medical students’ essay competition, 5th-year medical student at the University of Pernambuco (Universidade de Pernambuco) in Brazil.