How Trauma Affects The Brain and Memories
As trauma therapists, we are often asked questions like, how does trauma affect the brain?
Many people who have experienced trauma struggle with fragmented memories, intense emotions, and physical sensations they can't explain. Understanding the sciencey, neurobiology of trauma, can provide insights into these experiences and start to clear a path for healing.
How Does Trauma Affect the Brain Long Term?
Trauma affects the brain in profound and lasting ways, especially when it occurs during early childhood or as a result of repeated traumatic events. When a person experiences trauma, the brain’s structure and function can change, particularly in areas responsible for emotional regulation, memory, and the stress response. The brain’s stress system, known as the hypothalamic-pituitary-adrenal (HPA) axis, is activated during traumatic events, flooding the body with stress hormones like cortisol and adrenaline. These stress hormones are meant to help us survive immediate danger, but when trauma exposure is ongoing or overwhelming, they can disrupt normal brain development and alter brain chemistry.
This disruption can lead to difficulties in regulating emotions, forming coherent memories, and coping with daily life. Over time, trauma exposure increases the risk of developing mental health disorders such as anxiety, depression, and post-traumatic stress disorder (PTSD). It can also contribute to substance use disorders and self-destructive behavior, as individuals may turn to substances or risky actions in an attempt to self-soothe or escape emotional pain. Research shows that the effects of trauma on the brain are not just psychological but deeply biological, affecting the way the brain develops and functions throughout life.
The Brain's Response to Trauma
When a person experiences a traumatic event, their brain undergoes significant changes to ensure survival. The brain is structured in layers, with the most basic survival instincts at the bottom and higher-level thinking at the top. Trauma can alter specific brain regions, such as the amygdala, hippocampus, and prefrontal cortex, which are involved in processing fear responses, memory, and emotion.
During trauma, the lower, more primitive areas of the brain take control.
The survival brain, also known as the reptilian brain, initiates automatic responses like increased heart rate, muscle tension, and rapid breathing. These responses are part of the brain entering survival mode during trauma, where it becomes highly focused on immediate safety and threat response. This allows for quick reactions without conscious thought.
The emotional brain, or limbic system, processes emotions and memories. Within this system, the amygdala acts as the brain’s alarm system, while the hippocampus typically helps store and contextualize long-term memories (the functions of these areas of the brain are important for understanding trauma responses).
However, during trauma, the thinking brain - specifically the prefrontal cortex - often becomes much less active. This part of the brain, responsible for rational thinking and emotional regulation, may shut down, leaving the survival and emotional brains in charge.
The Role of the HPA Axis in Trauma
Understanding how the body’s stress system shapes our response and memory formation during traumatic events.
The HPA axis, or hypothalamic-pituitary-adrenal axis, is a central part of the body’s stress response system. When a person faces a traumatic event, the HPA axis is activated, releasing stress hormones that prepare the body to respond to danger. While this response is essential for survival, repeated or intense activation—such as during ongoing trauma—can lead to dysregulation of the HPA axis. This dysregulation is often seen in people who have experienced significant trauma, and it can have a lasting impact on mental health.
When the HPA axis is overactive, it can make it harder for the brain to regulate emotions, leading to increased emotional distress, anxiety, and difficulty coping with stress. The flood of stress hormones also affects how memories are formed and stored, which is why traumatic memories can feel fragmented, intrusive, or difficult to process. Research shows that early intervention and the development of healthy coping strategies can help regulate the HPA axis, reducing the risk of developing trauma-related disorders.
Seeking support from mental health professionals and learning effective ways to manage stress are important steps in healing. By understanding how the HPA axis influences our emotions and memories, individuals can begin to develop coping skills that support recovery and well-being, even after experiencing traumatic stress.
Trauma and Memory
Trauma can profoundly impact how memories are formed and recalled. Trauma can impair memory function, particularly affecting the hippocampus, which is critical for processing and storing verbal declarative memories. Understanding this can help explain why trauma survivors often struggle with fragmented or intense memories. Additionally, sleep disturbances are common in trauma survivors and can further disrupt memory function.
There are two main types of memories affected by trauma:
Body Memories, or implicit memories, are stored in the survival brain. These are the sensations and emotions your body holds onto, even if you can’t articulate them in words.
You might experience sudden anxiety, nausea, or a feeling of being frozen without understanding why. These memories can be triggered automatically by sensory cues related to the traumatic event. For example, the sound of a slamming door might trigger intense fear or intrusive thoughts, even if you don't consciously remember the original trauma.
Story Memories, or explicit memories, form the narrative of what happened.
These include factual details like time, place, and sequence of events. Trauma can disrupt the formation of these memories, leading to gaps or inconsistencies in recall. For example, someone might feel fear or confusion when trying to remember the sequence of events after a traumatic experience, as the narrative memory is fragmented. This is partly due to the impaired functioning of the hippocampus during traumatic events.
During trauma, the brain’s priority is survival, not creating a coherent narrative.
As a result, the amygdala might store vivid sensory details - a particular smell, sound, or bodily sensation - while the hippocampus struggles to place these details in context. This is why certain triggers can evoke intense feelings or bodily reactions, even if the full cognitive memory of the event is unclear.
The Limitations of Cognitive Trauma Treatment Approaches
Understanding how trauma affects the brain explains why purely cognitive or “talk therapy” approaches may fall short in treating trauma. It is crucial to provide a safe environment for trauma survivors, where they feel supported and secure as they process their experiences.
When traumatic memories are stored and manifest as bodily sensations, trying to “think your way out” of trauma responses often proves ineffective. In addition to cognitive strategies, supporting trauma recovery requires healthy ways of coping and fostering positive experiences with caring adults, which can help buffer the negative impacts of trauma and promote resilience.
Why?
To summarize the sciencey visual above, traumatic memories are often stored in non-verbal, sensory-based forms in regions of the brain
The amygdala plays a key role in encoding emotional aspects of traumatic experiences.
The hippocampus, responsible for contextualizing memories, may be impaired during trauma, leading to fragmented or implicit memories. Trauma during the developing brain, especially when it involves life threatening events or sexual abuse, can have lasting effects on memory and emotional regulation due to changes in brain structures like the hippocampus and amygdala.
Purely cognitive approaches primarily engage the areas of the brain that are responsible for logic, language, and analytical thinking .
Trauma is stored in areas of that brain, which are in charge of body-based sensations, intuition, nonverbal communication, empathy, forming healthy attachments, creativity and emotional memory
Because cognitive approaches (language, logic etc) engage other areas of the brain, trauma often remains untouched by cognitive strategies alone.
The disconnect between cognitive understanding and emotional/bodily experiences of trauma explains why trauma survivors might “know” they’re safe but still feel threatened.
Trauma can also impact the brain areas responsible for language and self-expression.
This is why many trauma survivors might find it challenging to articulate their experiences or feelings, both immediately after the event and later in life. It’s important to recognize that this difficulty is a normal response to trauma, not a personal failure.
Healing from Trauma
The good news is that healing from trauma is possible, even if you can’t remember everything that happened.
The brain’s neuroplasticity - its ability to form new neural connections - allows for recovery and growth. Even adults who experienced trauma in childhood can benefit from neuroplasticity and make significant progress in healing. Effective trauma treatment often involves approaches that address both the mind and body, such as EMDR Therapy (Eye Movement Desensitization and Reprocessing) or Somatic Experiencing. Trauma survivors face a heightened risk of substance abuse and self harm, so it is important that therapy addresses these challenges as part of the recovery process.
These therapies can help process traumatic memories and sensations stored in the body, even when they can’t be fully verbalized. They work to integrate fragmented memories and reduce the intensity of trauma responses over time.
It’s crucial to work with a therapist who understands trauma and can provide a safe, supportive environment for healing. Individuals are encouraged to seek support from professionals, support groups, and others who have experienced similar trauma, as connecting with those who understand can be an important part of recovery.
Remember, your brain's reaction to trauma was designed to protect you.
As you move along your healing journey, our hope is that you can be patient and compassionate with yourself. Healing is possible, no matter how long ago the trauma occurred.
Understanding the neurobiology of trauma can be empowering.
It provides a framework for understanding your experiences and reactions, which can reduce self-blame and shame. Remember, your responses are normal reactions to emotionally overwhelming circumstances.
With time, support, and appropriate interventions, you can reclaim a sense of safety, wholeness, and peace.
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