Peace in Colombia requires healing the scars of conflict on the mind and brain

Standfirst

Resurging violence in Colombia is silently embedding a mental health crisis driven by trauma, mass displacement, and ecological collapse.

Colombia’s six-decade armed conflict has resulted in the displacement of over several million people and more than 350,000 deaths, making it one of the world’s longest and deadliest internal conflicts¹. Rooted in political exclusion and land inequality, the conflict escalated in the 1960s with the rise of guerrilla groups like the FARC and ELN, later sustained by illicit economies in neglected rural regions. In response, paramilitary forces such as the AUC emerged, intensifying violence, human rights violations, and forced displacement. Beyond the human toll, the conflict has fractured institutions, eroded social cohesion, and severely undermined public health and environmental systems, particularly in rural areas.

The 2016 peace agreement in Colombia, signed between the government and the FARC guerrilla group, marked a significant step toward ending decades of conflict. The agreement included provisions for a truth commission, transitional justice, and the FARC laying down their arms.

Despite this agreement representing a historic opportunity for national reconciliation, violence is again on the rise. The agreement has failed to address the entrenched structural and territorial inequalities driving conflict. In early 2025 alone, Colombia recorded its largest mass displacement event on record, with more than 52,000 people forcibly displaced, 8,600 confined due to violence risk, and 19,000 subjected to movement restrictions in the Catatumbo region. Nationally, an additional 5,452 people were displaced and 11,896 confined during the same period.

A transformed geography of violence, ecological collapse, and inequality

The landscape of conflict-related violence and displacement has shifted significantly between the pre-agreement (2009–2016) and the post-agreement (2016–2025) periods (Figure 1a–b). While earlier patterns reflected more consolidated territorial control by major armed groups, recent years show a more fragmented and dispersed geography of violence. These changes intersect with growing environmental degradation and social vulnerability, particularly in regions with intensified coca cultivation and illegal mining.

Figure 1. Conflict-related exposures and multilevel mechanisms linking violence to brain and mental health in Colombia.

Panel a depicts conflict-related indicators during the pre-peace agreement period (2009– 2016), while panel b covers the post-agreement period (2016–2025). Maps show the spatial distribution of forced displacement, illegal mining, and coca cultivation across Colombian municipalities, as well as the presence and territorial shifts of armed groups. Data were obtained from the United Nations Office on Drugs and Crime (UNODC), the Internal Displacement Monitoring Centre (IDMC), and the Victims Unit (Registro Único de Víctimas – RUV). Panel c presents a conceptual framework linking structural violence and social adversity to brain and mental health outcomes via behavioral, physiological, and biological pathways. Adversities are organized into three domains: (1) structural and environmental factors (e.g., forced displacement, inequality, dispossession), (2) community and psychosocial stressors (e.g., malnutrition, parental stress, instability), and (3) exposome and biological mediators (e.g., inflammation, HPA axis dysregulation, microbiota). These domains interact through allostatic load mechanisms, leading to mental health outcomes and brain changes. The central figure highlights the cumulative burden of violence and deprivation, illustrating how chronic exposure becomes biologically embedded in conflict-affected populations.

Following the peace agreement, illegal armed actors quickly reorganized and seized control of strategic areas for coca cultivation, illegal mining, and trafficking routes to regain influence and resources. The simultaneous withdrawal of state institutions from peripheral regions and the collapse of the Venezuelan state has created a governance vacuum, reigniting territorial disputes and deepening humanitarian and environmental crises². Since 2016, Colombia has recorded 1,4 million new internal displacements, averaging 180,000 newly displaced persons per year³. Many former combatants, victims, and displaced people have relocated to the peripheries of major cities, creating vulnerable communities characterized by low socioeconomic status, limited healthcare access, and persistent exposure to violence (Figure 2).

Figure 2. Scenes of displacements.

An aerial view of Bogotá’s southern district, Ciudad Bolívar, where waves of rural and Venezuelan migrants displaced by conflict and economic hardship have reshaped the urban landscape, creating a dense patchwork of formal and informal settlements clinging to the hillsides. Since signing the 2016 Peace Agreement, over 1.4 million new displacements have been registered within Colombia as of August 2024, representing an annual average of 180,000 new internally displaced persons (IDPs)⁵ (Credits: Johnny Miller).

Narco-deforestation, an environmental consequence of failed drug policies⁴, is one of the most evident effects of this breakdown. In biodiversity hotspots such as Catatumbo, Nariño, and Putumayo, the expansion of coca cultivation has accelerated deforestation in areas controlled by illegal armed actors. These territories, home to Indigenous, Afro-Colombian, and campesino communities, now face an overlay of violence, socioeconomic vulnerability, land dispossession, and environmental devastation. Many have suffered multiple cycles of forced displacement, often without access to basic needs, with over nine million cases estimated in the national registry over the past six decades. Since the signing of the peace agreement, deforestation in Colombian protected areas has increased dramatically by 177%, with parks such as Serranía de la Macarena and Tinigua experiencing severe losses due to unregulated extractive activities⁵. These landscapes, relatively preserved under guerrilla control, have been overtaken by criminal and extractive interests, transforming ecological sanctuaries into conflict zones.

Currently, illegal armed groups operate in 73% of municipalities, and eleven humanitarian emergency zones remain active. This crisis, which evidences not only conflict resurgence but also persistent institutional neglect, creates a complex landscape of structural violence with enduring social, ecological, and brain and mental health consequences.

The mental and brain health consequences of adversity

Evidence from other nations confirms an exponential relationship between poverty, mental illness, and brain health threats (Figure 1c). Deprivation increases vulnerability to common mental disorders, while untreated mental illness undermines educational attainment, employment opportunities, and social mobility⁶. This vicious cycle remains unbroken in Colombia’s rural regions, silently eroding individual agency and collective development. Economic deprivation further exacerbates depression and anxiety through chronic stress, reduced cognitive resilience, and persistent barriers to care. However, the consequences extend beyond clinical pathology, as forced displacement brings the psychological burden of loss, uprooting, and the rupture of community structures. These disruptions weaken social ties and hinder the formation of support networks in resettlement contexts, reinforcing isolation, disconnection, and long-term deterioration of brain and mental health.

Recent large-scale studies across Latin America and Colombia demonstrate that structural inequality becomes biologically embedded, amplifying the burden of disease and undermining brain and mental health. Countries with higher income inequality are significantly associated with reduced brain volume and altered functional connectivity⁷. Compared to chronological age, older brain age is systematically higher in Latin American and Colombian cohorts⁸. The combined exposome of physical (climate change and agrochemical pollution), social (socioeconomic inequality and migration), and sociopolitical (democratic instability) adversities accelerate aging, especially among the most vulnerable populations⁹. These findings are especially relevant in Colombia, where chronic adversity, territorial conflict, and institutional fragility intensify these neurobiological vulnerabilities.

The burden of displacement

When forced displacement is added to adversity, the consequences on brain and mental health become even more severe. The mental health burden among Colombia’s conflict-affected populations ranks among the most persistent and widespread documented globally. A recent meta- analysis¹⁰ of over 15,000 individuals exposed to armed conflict, including internally displaced Colombians, estimated current prevalence rates of 31% for post-traumatic stress disorder (PTSD), 25% for major depressive disorder, and 14% for generalized anxiety disorder. These rates were markedly elevated in underserved settings where fragile healthcare infrastructure, persistent violence, and institutional abandonment foster a syndemic of trauma and structural neglect.

Worldwide, nearly one in four individuals living in conflict-affected settings experience a mental health disorder, and approximately 5% suffer from severe conditions such as PTSD or major depression¹¹. Large-scale meta-analyses of conflict-affected populations have shown that sustained exposure to war and displacement leads to enduring symptoms of anxiety, depression, and PTSD, often persisting long after the violence ends. Cumulative trauma has emerged as the strongest predictor of psychiatric morbidity, a pattern deeply entrenched in Colombia’s multigenerational armed conflict¹². Yet Colombia’s unique epidemiological context may worsen these effects, with prolonged displacement, ecological collapse, and institutional delays compounding the brain and mental health toll of ongoing conflict (Figure 1c).

Neurobiological consequences of chronic violence

The syndemics of violence and displacement profoundly impact brain and mental health. Chronic exposure to violence and forced displacement disrupts allostatic regulation, triggering sustained activation of the hypothalamic-pituitary-adrenal (HPA) axis and leading to multisystem dysregulation. Hormonal imbalances, including altered cortisol secretion and circadian disruption, immune dysfunction, cardiovascular strain, and metabolic alterations, characterize this state of allostatic overload¹³. These physiological changes heighten vulnerability to psychiatric and somatic disorders and are especially pronounced in individuals exposed to cumulative lifetime adversity.

Moreover, chronic trauma alters brain structure and function in regions involved in memory, emotional regulation, and stress response, such as the hippocampus, amygdala, and prefrontal cortex, compromising cognitive resilience and adaptive capacity¹⁴. The multimodal nature of the exposome offers a powerful lens to capture the full scope of interacting biological disruptions resulting from chronic adversity¹⁵. Lifelong exposure to adverse environments, socioeconomic inequality, and psychosocial stressors leads to allostatic overload, activating biological stress responses from molecular pathways to entire body systems and undermining long-term health. In regions like rural Colombia, where armed conflict, ecological degradation, and structural inequality intersect, socially rooted vulnerabilities shape declining trajectories of brain and mental health (Figure 1c). Embracing an exposome-informed, One Health perspective may help address the complex interplay of environmental, biological, and institutional forces driving neurodevelopmental and neuropsychiatric outcomes.

Bridging science and policy into a health priority initiative

Despite the above compelling evidence, brain and mental health remain sidelined in Colombia’s post-conflict agenda. Mental health services are chronically underfunded, trauma-informed care is scarce, and culturally adapted interventions are mainly absent. Community-based mental healthcare remains fragmented, with few initiatives integrating brain and mental health care, epidemiology, and social determinants into a cohesive strategy. Confronting the consequences of chronic violence demands coordinated action from national health authorities, regional governments, international agencies, and global health actors. It also requires systematically integrating brain and mental health into Colombia’s primary healthcare and peacebuilding efforts. We believe that a set of recommendations (Table 1) is critically needed to mitigate the impact of conflict in Colombia and other populations displaced by conflict

Table 1 |.

Recommendations to address brain and mental health in Colombia

Category	Recommendations	Goal	Proposed actions
Healthcare	Expand trauma-informed, community-based mental healthcare and address infrastructure gaps in rural/conflict zones.	Improve equitable access to mental health services in underserved areas.	Train local providers, deploy mobile units, build permanent centers, and integrate services into primary care.
Policy	Embed brain and mental health into peacebuilding agendas and develop intersectoral strategies across health, education, environment, and justice.	Integrate mental health into national recovery frameworks and address structural determinants.	Mandate mental health in post-conflict policies and create inter-ministerial task forces to coordinate implementation.
Research	Fund interdisciplinary studies on the biological embedding of adversity and apply exposome-informed, One Health approaches.	Understand how conflict-related adversity biologically impacts brain health across levels of analysis.	Support longitudinal and multimodal studies linking environmental, social, and biological factors across the lifespan.
Community	Co-design interventions with marginalized groups and promote resilience through arts, education, and cultural programs.	Enhance relevance, engagement, and wellbeing in vulnerable populations.	Use participatory methods to develop culturally grounded programs and support creative community-based initiatives.

First, trauma-informed, community-based care must be strengthened in conflict-affected and historically marginalized regions. Mental health services must be decentralized, culturally tailored, and integrated into primary care systems. This requires sustained investment in mobile health infrastructure, training of local providers, and long-term support for services in rural, Indigenous, Afro-Colombian, and displaced communities, where access remains most limited.

Second, brain and mental health must be embedded within national recovery and peacebuilding strategies. Neuroscience-informed interventions should be incorporated into Colombia’s transitional justice programs, reparations initiatives, and broader social policy frameworks. Psychological trauma related to displacement, dispossession, and territorial violence must be treated not as an ancillary issue but as a core determinant of human rights, public health, and social cohesion. This effort demands sustained collaboration across health, education, environment, and justice sectors.

Third, interdisciplinary research, bridging neuroscience, public health, and social sciences, must be prioritized to inform policy and enable scalable, evidence-based interventions. Investment is needed to understand how violence becomes biologically embedded and intergenerationally perpetuated. Research should focus on neurodevelopment, cognitive and emotional development, epigenetics, and the neuropsychological impact of chronic adversity.

A deeper understanding of how structural violence shapes brain and mental health can guide more effective prevention, intervention, and reintegration strategies, as well as critical national recovery and peacebuilding components. Colombia’s case provides an urgent lesson for global health: achieving sustainable peace requires confronting the hidden mental and brain health toll of violence and inequality.