What happens at the cellular level when we experience adversity?

Adverse experiences can lead to cells becoming specialized in stress responses, potentially predisposing them to future activation, or becoming fatigued from overwork, leading to dysfunction. These cellular changes can persist even if the individual has forgotten the traumatic event.

Does time heal all wounds when it comes to trauma?

While time can help, it's not a complete cure for everyone. On average, people who experience adversity are more likely to face health challenges, but there is significant individual variability and remarkable resilience. Understanding this variability is key to intervention.

How common are adverse experiences?

Adverse experiences are remarkably common. In the US, about 75-80% of people will experience some form of adversity in their lifetime. Studies show about half of children encounter meaningful adversity before adulthood.

Can different types of adversity have different biological effects?

Yes, the type of adversity matters. Trauma threatening survival, like abuse or violence, specifically impacts amygdala reactivity. Deprivation, like neglect, influences brain systems involved in cognitive and social development. Threat, however, can lead to similar cardiovascular effects regardless of its specific form.

What are the implications for public health and social policy?

Understanding the biology of adversity highlights the need for policy-level solutions. For example, increased cash assistance for families in poverty was shown to significantly reduce the impact of economic adversity on children's brain development and mental health.

What are promising new treatments for trauma?

Emerging treatments include 'bottom-up' approaches like trauma-informed yoga, which focuses on the body's sensations and choice, showing equal effectiveness to cognitive processing therapy in reducing PTSD symptoms. These methods are often more accessible.

What are the key ingredients for resilience?

Resilience is often fostered by 'ordinary magic', such as social support from others, determination, and having meaning and purpose. Having just one supportive adult can be incredibly powerful for children facing adversity.

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Harvard Thinking: The things we carry

Harvard University

Education3 min read34 min video

Mar 20, 2026|1,023 views|68|2

Samantha Laine Perfas Karestan Koenen Kate McLaughlin Jason Buenrostro biology of adversity Broad Institute Harvard Medical School cellular biology adversity trauma trauma care trauma treatment

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Key Moments

TL;DR

Adversity alters cells, impacting physical and mental health. Science reveals deep biological links and potential interventions.

Key Insights

Adverse childhood experiences (ACEs) are linked to increased risks of various mental health issues (PTSD, depression, anxiety, psychosis) and physical ailments (cardiovascular disease, diabetes, autoimmune disorders, dementia).

The impact of adversity is often dose-dependent; the more adverse experiences, the higher the health risks.

Scientific advances allow us to observe the effects of adversity at the cellular level, revealing how cells can adapt, become fatigued, or develop dysfunctions due to chronic stress.

Short-term adaptive stress responses can become detrimental when chronically activated, negatively impacting the brain, particularly areas like the amygdala, which can lead to increased risk for mental health problems.

The type of adversity (e.g., threat vs. deprivation) and the timing of exposure (childhood, adolescence, fetus) can lead to different biological and neurological effects.

Social support, finding meaning and purpose, and policy-level interventions (like economic assistance) are crucial factors in resilience and mitigating the negative impacts of adversity.

THE PERVASIVE REACH OF ADVERSITY

Adverse experiences, particularly during childhood, have profound and lasting effects on both mental and physical health. These can range from common mental health disorders like PTSD, depression, and anxiety to a heightened risk of serious physical conditions such as cardiovascular disease, type 2 diabetes, autoimmune diseases, and even dementia. This connection is well-established, with research showing that the risks associated with early adversity persist across the lifespan and can even extend to subsequent generations.

DOSE-DEPENDENT EFFECTS AND CELLULAR CHANGES

A significant finding in the study of adversity is the 'dose-response' relationship: the more types of adverse experiences an individual endures, the greater their risk for developing health challenges. Even with strong coping mechanisms and resilience factors, accumulating adversity can significantly impact health outcomes. At a cellular level, these experiences can alter the stress response pathways. Some cells may become hyper-vigilant, while others may become fatigued, leading to broader physiological dysfunction.

ADAPTIVE RESPONSES AND LONG-TERM CONSEQUENCES

The body's stress responses, designed for short-term survival, can become harmful when persistently activated by chronic adversity. This is particularly evident in the brain, where over-activation of systems like the amygdala—responsible for threat detection—can lead to an increased predisposition for mental health issues. While adaptive in dangerous environments, this hyper-reactivity can predict future problems like PTSD when individuals encounter further traumatic events.

DIFFERENT TYPES OF ADVERSITY, DIFFERENT IMPACTS

The nature of the adverse experience matters. Threats to survival, such as abuse or violence, tend to impact brain regions involved in threat perception, like the amygdala. In contrast, experiences of deprivation, such as neglect, can disproportionately affect brain systems related to cognitive and social development. These distinctions highlight that while some biological responses to adversity are common, others are specific to the type of stressor encountered and its timing in life.

EPIGENETICS AND CELLULAR MEMORY

Cells possess a form of memory, a concept illuminated by epigenetics, where past exposures can be recorded without altering the underlying DNA sequence. This means that even if an individual no longer actively thinks about past traumas, cellular changes may still manifest, potentially contributing to health problems. Understanding this cellular memory is crucial for identifying risks and potentially intervening before symptoms become severe or diseases develop.

RESILIENCE, INTERVENTION, AND POLICY SOLUTIONS

Despite the profound negative impacts of adversity, resilience is the most common response. Factors like social support from even one trusted individual, finding meaning and purpose, and accessible, body-based therapies (like trauma-informed yoga) can significantly buffer these effects. Furthermore, policy-level interventions, such as economic assistance for families, have demonstrated a substantial reduction in the negative impacts of adversity on children's brain development and mental health, suggesting societal shifts are vital.

FUTURE DIRECTIONS AND HOPE

The future of this research holds promise for developing objective measurement tools to assess treatment effectiveness and match individuals with the most beneficial interventions. By understanding the biological mechanisms of adversity, scientists aim to create more targeted treatments and strengthen resilience. The prevalence of resilience and the "ordinary magic" of social support and purpose offer significant hope for individuals and future generations, indicating that natural sources of strength are often within reach.

Mentioned in This Episode

●Supplements

●Software & Apps

●Organizations

●Concepts

●People Referenced

Common Questions

Adverse childhood experiences (ACEs) are linked to a host of negative outcomes, increasing the risk for mental health issues like PTSD, depression, and anxiety, as well as physical conditions such as cardiovascular disease, type 2 diabetes, autoimmune diseases, and dementia, often persisting across the life course and even across generations.

Topics

Brain Development Health & Longevity Neuroscience & the Brain Mental Health & Psychology Public Health Policy Stress Biology Trauma Treatment Adverse Childhood Experiences Cellular Mechanisms Resilience Factors

Mentioned in this video

Software & Apps

trauma-informed yoga

A body-based approach to healing trauma that focuses on bodily sensations and choice, shown to have equal effectiveness as cognitive processing therapy in reducing PTSD.

hippocampus

A brain region crucial for learning and memory, which has been observed to decrease in size in individuals who experienced trauma or grew up in poverty.

hypothalamus

A part of the brain that controls physiological functions. It is suggested that deeper brain functions controlled by structures like the hypothalamus may show more convergence in response to different stressors.

cognitive processing therapy

An evidence-based cognitive behavioral therapy for PTSD that involves working through traumatic memories. It was compared to trauma-informed yoga, showing equal effectiveness in reducing PTSD symptoms.

Apple Podcasts

A podcast app developed by Apple Inc. Listeners are encouraged to rate and review the podcast on Apple Podcasts.

amygdala

A region of the brain's temporal lobe, responsible for processing emotions such as fear and aggression. It shows increased responsiveness in children exposed to trauma.

Organizations

Massachusetts General Hospital

A teaching hospital affiliated with Harvard Medical School. Colleagues there have linked amygdala signatures to markers of cardiovascular disease.

Harvard T.H. Chan School of Public Health

Academic institution where Kristen Conan is a professor of psychiatric epidemiology.

Broad Trauma Initiative

An initiative directed by Kristen Conan at the Broad Institute, focusing on trauma.

Harvard University

Institution where Jason Ben Roster is a professor in the department of stem cell and regenerative biology.

Broad Institute

An institute associated with Harvard University and MIT, involved in biological research, including the biology of adversity project.

University of Oregon

The university where Kate McLachlin is the executive director of the Balmer Institute for Children's Behavioral Health.

Balmer Institute for Children's Behavioral Health

An institute where Kate McLachlin is the executive director, focusing on children's behavioral health.

People

Natalie Slopin

A colleague of the speakers whose published paper discussed the positive impact of housing support payments on mitigating negative outcomes associated with child experiences and adversity.

Romanian orphans

Refers to children from Romanian orphanages, studied for the effects of deprivation on development and brain systems involved in cognitive and social development.

Kristen Conan

Professor of psychiatric epidemiology at the Harvard T.H. Chan School of Public Health and an institute member at the Broad Institute, directing the Broad Trauma Initiative. Focuses on the persistence of adversity effects.

Samantha Ly Perfos

Host of Harvard Thinking and a writer for the Harvard Gazette. Facilitates the discussion on adversity and its biological impacts.

Kate McLachlin

Executive director of the Balmer Institute for Children's Behavioral Health at the University of Oregon, formerly a professor of psychology at Harvard. Discusses the impact of adverse experiences on mental and physical health.

Ann Masten

A researcher from the University of Minnesota who coined the term 'ordinary magic' to describe the common, accessible factors that promote resilience.

Jason Ben Roster

Professor at Harvard University in the department of stem cell and regenerative biology, and director of the biology of adversity project at the Broad Institute. Discusses cellular-level impacts of adversity.

Holocaust survivors

Individuals who survived the genocide perpetrated by Nazi Germany during World War II. Their descendants were part of early studies on intergenerational effects of trauma.

Concepts

Epigenetics

The study of changes in organisms caused by modification of gene expression rather than alteration of the genetic code itself. It plays a role in how cells remember past exposures.

Companies

Spotify

A digital music, podcast, and video streaming service. Viewers are encouraged to rate and review the podcast on Spotify.

Supplements

cortisol

A steroid hormone produced by the adrenal cortex, often referred to as the 'stress hormone'. Patterns of cortisol production can show similar changes across different types of adversity.

Media

Harvard Gazette

Publication for which Samantha Ly Perfos writes, associated with Harvard University.