What Is Post-Traumatic
Stress Disorder?

Defining Trauma & PTSD

Trauma is an emotional and psychological response to an event or series of events that overwhelm an individual's capacity to cope. It can result from a single catastrophic incident — a car accident, assault, natural disaster, or sudden loss — or from prolonged exposure to threatening, distressing, or disturbing circumstances over time.

Post-Traumatic Stress Disorder (PTSD) is a diagnosable mental health condition that develops in some individuals following exposure to one or more traumatic events. It is characterized by persistent, involuntary re-experiencing of the trauma, avoidance of trauma-related stimuli, negative alterations in cognition and mood, and marked changes in arousal and reactivity.

"Trauma is not just an emotional shock. It is an experience so overwhelming that the brain cannot process it in the usual way — leaving it raw, vivid, and dangerously close to the present moment." — Dr. Suzana Flores

The key distinction between a normal stress response and PTSD lies in persistence and impairment. While most people experience acute distress after trauma, PTSD is diagnosed when symptoms persist for more than one month and cause significant disruption to daily functioning, relationships, and quality of life.

A Brief History of PTSD

The recognition of trauma's lasting psychological effects has a long — and often painful — history. For centuries, the suffering of those exposed to extreme events was dismissed, misunderstood, or blamed on the individual.

Civil War Era: "Soldier's Heart"

During the American Civil War, physicians observed soldiers experiencing racing heart, anxiety, and profound fatigue long after combat ended. They called it "Soldier's Heart" or Da Costa's Syndrome — attributing it to cardiac dysfunction rather than psychological injury.

World War I: Shell Shock

The term "Shell Shock" emerged from the trenches of World War I, where soldiers exhibited trembling, paralysis, mutism, and flashbacks after prolonged artillery bombardment. British physicians Charles Myers and W.H.R. Rivers began documenting these responses systematically. Many soldiers were court-martialed for cowardice before the medical community began to recognize the legitimacy of psychological injury.

World War II: Combat Fatigue

By the Second World War, military psychiatrists used terms like "Combat Fatigue" and "War Neurosis." Early forms of psychological first aid emerged. The work of psychiatrists like Roy Grinker and John Spiegel moved understanding forward, but returning veterans still faced significant stigma.

Vietnam Era & the Birth of PTSD

The experience of Vietnam veterans — combined with the growing women's liberation movement documenting the psychological aftermath of rape and domestic violence — catalyzed a sea change in the field. Advocates including Chaim Shatan and Robert Lifton lobbied the American Psychiatric Association to formally recognize the syndrome. In 1980, PTSD was included for the first time in the third edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-III).

DSM-5 & Modern Understanding

Today, PTSD appears in the DSM-5 (2013) under a new category: "Trauma- and Stressor-Related Disorders." The updated criteria broadened the definition of qualifying traumatic events and added more nuanced symptom clusters. Research into the neurobiology of trauma has transformed treatment approaches — moving from talk therapy alone to a sophisticated array of evidence-based interventions including EMDR, somatic therapies, and pharmacological support.

Causes & Risk Factors

Not everyone who experiences trauma develops PTSD. Research shows that PTSD intensity and likelihood are shaped by a constellation of three categories of factors, as described by Dr. Flores in her clinical work:

1. Pre-Event Factors

• Previous exposure to trauma, particularly childhood neglect or abuse
• Prior mental illness — depression, anxiety, or childhood emotional difficulties
• Family instability — domestic violence, separations, financial hardship
• Absence of social support and connection
• Early substance use or behavioral difficulties
• Biological factors — genetic predisposition to anxiety disorders

2. Event Factors

• Level of exposure to the traumatic event (audio vs. visual, witness vs. direct participant)
• Perceived level of threat to life
• Age at which the trauma occurs (early childhood exposure carries greater risk)
• Multiple traumas or extended duration of traumatic exposure
• Existence of ongoing threat — active war zones, domestic violence, abuse situations
• Military combat and multiple deployments
• Occupational exposure — first responders, emergency medicine, law enforcement

3. Post-Event Factors

• Quality of social support network following the trauma
• Ability or inability to find meaning in the suffering
• Whether physiological arousal subsides or remains chronically elevated
• Access to timely, quality mental health care
• Additional life stressors following the traumatic event

Symptoms of PTSD

The DSM-5 organizes PTSD symptoms into four major clusters. Individuals must experience symptoms from all four clusters for a minimum of one month, with significant functional impairment, to meet diagnostic criteria.

PTSD & the Brain

Modern neuroscience has revealed that PTSD is not simply a psychological response — it is a neurobiological condition that produces measurable changes in brain structure and function. Understanding these changes is critical to appreciating why trauma survivors experience symptoms that may seem irrational from the outside.

The Amygdala — The Alarm System

The amygdala, responsible for detecting and responding to threats, becomes hyperactive in PTSD. It fires threat responses to stimuli that superficially resemble elements of the original trauma — a smell, a sound, a tone of voice — even when there is no actual danger. This is why trauma survivors can experience intense fear responses that appear disproportionate to the situation.

The Hippocampus — Memory Integration

The hippocampus plays a central role in contextualizing memories — placing them in time and understanding that a past event is in the past. Research consistently shows hippocampal volume reduction in individuals with PTSD. This impairs the brain's ability to "timestamp" traumatic memories, leaving them feeling immediate and present — the neurological basis of flashbacks.

The Prefrontal Cortex — Rational Regulation

The prefrontal cortex — the "thinking brain" — is responsible for reasoning, emotional regulation, and decision-making. In PTSD, its activity is suppressed. This means that during a trauma response, rational thought and emotional regulation are literally less available to the survivor.

"The trauma brain is not a broken brain. It is a brain that learned, under extreme conditions, to prioritize survival above all else. Healing means teaching the nervous system that survival mode is no longer needed."

Complex PTSD (C-PTSD)

While standard PTSD typically arises from a single traumatic event or a brief period of exposure, Complex PTSD (C-PTSD) develops from prolonged, repeated, and often inescapable traumatic experiences. Examples include:

• Childhood physical, emotional, or sexual abuse
• Domestic violence — particularly long-term relationships
• Narcissistic abuse in intimate relationships
• Captivity, torture, or prolonged exposure to conflict
• Long-term exploitation, trafficking, or coercive control

C-PTSD includes all the symptom clusters of PTSD, plus additional features that reflect the pervasive impact of sustained trauma:

• Emotional dysregulation — intense, volatile emotional responses disproportionate to triggers
• Negative self-concept — deep shame, worthlessness, or feeling permanently damaged
• Relational difficulties — profound distrust, difficulty maintaining close relationships
• Somatization — physical symptoms without medical explanation
• Dissociation — altered sense of self or reality, depersonalization

Learn more about Complex PTSD →

PTSD Is Treatable

Perhaps the most important message of modern trauma psychology is this: PTSD is highly treatable. With appropriate, evidence-based intervention, the vast majority of individuals experience substantial improvement — and many achieve full remission.

Effective treatments include EMDR, Trauma-Focused CBT, Prolonged Exposure therapy, Somatic Experiencing, and — in some cases — pharmacological support. The right approach depends on the individual's history, symptom profile, and personal preferences.