PTSD and Common Reactions to Trauma: Understanding What Happens After Trauma.
What is trauma?
Trauma is not defined only by what happened, but by how the nervous system experienced the event. Two people can go through the same situation and have very different responses. Trauma occurs when an experience is perceived as overwhelming, threatening, or inescapable, and the body is unable to fully process it at the time.
During trauma, the brain shifts into survival mode. Stress hormones increase, the amygdala becomes highly activated, and the nervous system prepares for fight, flight, freeze, or collapse. If the experience is not fully processed afterward, the body may continue responding as though the threat is still present, even when it is not.
How PTSD develops
Post-traumatic stress disorder (PTSD) develops when the nervous system remains stuck in a state of threat. Instead of the experience becoming a memory that feels located in the past, it continues to feel immediate and activating. Triggers can cause strong emotional, physical, or behavioural reactions that seem disproportionate to the present moment.
This happens because trauma affects how memories are stored. Rather than being organized as a coherent story, traumatic memories are often held as fragments such as sensations, emotions, images, or bodily responses. When something reminds the brain of the original danger, the nervous system reacts automatically to protect the person.
Acute stress disorder vs PTSD
In the early weeks following trauma, some people experience acute stress disorder. This includes symptoms such as intrusive memories, heightened anxiety, dissociation, sleep disruption, and emotional reactivity. Acute stress disorder occurs within the first few days to weeks after a traumatic event and can last up to one month.
For many individuals, these symptoms gradually settle as the nervous system processes the experience. PTSD is diagnosed when trauma symptoms persist beyond one month and continue to significantly interfere with daily functioning, relationships, or work.
PTSD vs complex trauma
PTSD is often associated with single-incident trauma such as a serious accident, assault, medical emergency, or natural disaster.
Complex trauma develops in response to repeated, chronic, or interpersonal trauma, particularly when it occurs in childhood or within relationships that were meant to provide safety. Examples include ongoing emotional abuse, neglect, domestic violence, or prolonged exposure to threat. In addition to PTSD symptoms, complex trauma often impacts self-worth, emotional regulation, identity, and attachment patterns, making relationships and trust especially difficult.
Common reactions to trauma
Trauma responses are normal, protective reactions to overwhelming experiences. They reflect how the nervous system learned to survive, even if those responses are no longer helpful. Common reactions include:
• Intrusive memories, flashbacks, or unwanted images
• Avoidance of reminders, places, conversations, or emotions
• Feeling constantly on edge, alert, or unsafe (hypervigilance)
• Emotional numbness or feeling disconnected from oneself or others
• Irritability, anger, or sudden emotional shifts, including inability to feel positive feelings
• Difficulty concentrating or remembering things
• Sleep problems, including insomnia or nightmares
• Physical symptoms such as increased tension, fatigue, headaches, etc.
These responses can come and go, change over time, or intensify during periods of stress or relational conflict.
Approaches to treating PTSD
Effective treatment for PTSD focuses on restoring a sense of safety, helping the nervous system regulate, and supporting the brain in processing traumatic memories rather than reliving them.
Cognitive Behavioural Therapy (CBT) helps individuals understand and shift trauma-related thoughts, reduce avoidance, and build coping strategies that support daily functioning.
Acceptance and Commitment Therapy (ACT) focuses on increasing psychological flexibility, helping people relate differently to trauma symptoms while reconnecting with personal values and meaningful actions that move them towards what they want and value.
Internal Family Systems (IFS) therapy views trauma responses as protective parts of the system and works to build internal trust, compassion, and safety so that wounded parts can be unburdened and heal.
Eye Movement Desensitization and Reprocessing (EMDR) supports the brain in reprocessing traumatic memories so they can be stored in a less distressing and more integrated way. EMDR also targets core beliefs that have been negatively impacted by trauma.
A progressive compassionate approach to healing trauma usually requires combing approaches to specifically focus on what makes the most sense for each individual.
Healing from trauma does not mean erasing the past. It means helping the body and mind recognize that the danger has passed and that new ways of responding are possible. If this resonates, support is available, and the contact page is there when you are ready to take the next step.
