The Science of How Mindfulness Relieves Post Traumatic Stress

An exploration of how traumatic stress affects the brain, and the research suggesting that mindfulness practices may help individuals be more equipped to handle the emotional and physical distress of PTSD.


Pain, loss and traumatic events are part of the human experience, yet most of us don’t talk about that part of our lives. According to a Health Care Policy report from Harvard Medical School, approximately 60% of North Americans experience at least one traumatic event in their lifetime. Some of these individuals may go on to develop post-traumatic stress disorder (PTSD), a condition marked by intense, disturbing thoughts and feelings related to a traumatic experience that last long after the traumatic event has ended. A recent review of the research finds that mindfulness-based programs such as Mindfulness-based Stress Reduction (MBSR) may provide relief from post-traumatic symptoms such as anxiety, sleep disturbance, and difficulty concentrating.

Understanding Post-Traumatic Stress Disorder (PTSD)

Post-traumatic stress and PTSD may occur after experiencing or witnessing a shocking or dangerous event. During the event, fear triggers a cascade of hormones like cortisol and adrenaline that flood the nervous system and mobilize the body’s defenses. Once the threat subsides, the nervous system usually “resets,” initiating the healing and recovery process. 

In some cases, or when stress is chronic, the system does not reset, and the physical and psychological effects of acute or prolonged stress manifest as symptoms of traumatic stress. Not everyone who survives a trauma develops PTSD, and not everyone with PTSD has experienced or observed a life-threatening event. Sudden, unexpected death or loss, or persistent environmental threat can also lead to a person developing post-traumatic stress symptoms. 

It is important to note that post-traumatic stress symptoms are not, in and of themselves, pathological. They represent the mind and body’s natural process of recovery following severe, often painful life experiences. Often more chronic and extremely traumatic events require longer periods of healing and repair.

As resilience builds, symptoms often lessen and eventually subside altogether. For some, however, post-traumatic symptoms can be accompanied by significant depression, anxiety, panic, and thoughts of suicide. In these cases, evidence-based treatment approaches under the care of a medical professional may be necessary to help alleviate the impacts of trauma. 

The Symptoms of PTSD

Although there are many causes of trauma, people with PTSD have a great deal in common. According to non-profit Anxiety and Depression Association of America, PTSD is characterized by three primary symptoms: 

  1. Repeating or reimagining the experience — Most have intrusive memories or bad dreams that occur in combination with physical symptoms like a racing heart and shortness of breath. 
  2. Avoidance— Individuals also tend to avoid objects, places, or events that trigger recollection of the initial experience, and learn to numb physical and emotional sensations when under duress. 
  3. Hyperactivity — The combination of unresolved nervous system hyperactivity and emotional distress can result in tension, anger, irritability, a tendency to startle easily, or difficulties coping with life events. This is often accompanied by difficulties sleeping, eating, and concentrating, and a tendency toward sadness, depression, social isolation, guilt, and a lack of trust in others and the world. 

How Traumatic Stress Affects the Brain

Acute and persistent traumas are also known to impact the structure and function of the brain and nervous system. Human and animal studies find that traumatic stress is associated with decreased volume in the hippocampus, anterior cingulate cortex, and left amygdala; brain regions that are highly sensitive to environmental threat. 

The hippocampus, part of the brain’s emotion processing center (limbic system), plays an important role in learning, memory, and emotion processing. It is particularly vulnerable to stress, and tends to be smaller in volume in those with PTSD.

The anterior cingulate links the limbic system to the prefrontal cortex—often referred to as the brain’s “thinking center.” It plays an important role in emotional regulation and cognitive flexibility. 

All told, these brain signaling anomalies may be related to greater difficulty regulating and coping with negative thoughts, feelings, and memories — a hallmark of post-traumatic stress.

The amygdala, another hub for cognitive and emotional processing, has also been found to be smaller in those with a history of trauma, although there doesn’t appear to be a connection between the size of the amygdala and the severity of PTSD symptoms. Researchers do believe that decreased regulation of the amygdala may be associated with an increased risk of developing post-traumatic symptoms or a diagnosis of PTSD. 

All told, these brain signaling anomalies may be related to greater difficulty regulating and coping with negative thoughts, feelings, and memories — a hallmark of post-traumatic stress.

But traumatic stress is not inevitable. For some, social support such as friends, family, or a support group, and a nervous system that is able to reset after a highly stressful event can reduce the odds of developing PTSD. For those with repeated exposure to extreme stressors, a history of adverse childhood events, a lack of social support, a history of psychological problems, or prolonged or chronic environmental threat, treatment is often a viable option to move from trauma to wellbeing. 

The Impact of Mindfulness-Based Treatment on PTSD

Historically, cognitive forms of psychotherapy with or without medication were the first line of treatment for PTSD. But many with PTSD avoid therapy due to social stigma, cost, guilt, shame, or an inability to seek help. In response to the need for alternative forms of treatment, more providers and trauma sufferers are turning to mindfulness-based interventions.

There is some debate among professionals as to whether mindfulness-based interventions for PTSD are effective. Some suggest that an increase in mindfulness may help individuals to better cope with intrusive thoughts and memories, and be more equipped to handle emotional distress. Correlational studies, which examine the relationship between two or more factors, show that higher levels of dispositional mindfulness are associated with fewer concurrent PTSD symptoms in survivors of natural disasters, victims of sexual abuse or assault, and firefighters.

Others suggest that mindfulness-based practices like meditation may cause considerable distress for some practitioners. For example, in a study of 60, adult meditators (43% female) and 32 meditation experts (25% female), 88% of participants reported “challenging or difficult meditation experiences [that] bled over into daily life…” that ranged from a few days to more than 10 years.

We have yet to understand what types of practices may, or may not exacerbate symptoms in those with a history of traumatic exposure. In addition, there are a number of well-researched conventional approaches such as cognitive therapy, eye movement desensitization and reprocessing (EMDR), and medications shown to reduce PTSD symptoms. There is some skepticism as to whether mindfulness alternatives are appropriate first-line therapies for PTSD. 

Do Mindfulness-Based Therapies Reduce Trauma Symptoms?

A meta-analysis of 18 studies compared the effects of mindfulness-based interventions to those of a randomized control group in reducing the psychological symptoms of traumatic stress and PTSD. This study included data on 1,219 participants. Researchers found that individuals who participated in the mindfulness-based interventions demonstrated significantly lower levels of PTSD symptoms following treatment than various control group members.

They also found that the longer the mindfulness intervention, the greater the reduction in traumatic stress symptoms. Additionally, individuals who received mindfulness-based interventions reported higher levels of mindfulness at the end of treatment compared to control group members.

Researchers found that individuals who participated in the mindfulness-based interventions demonstrated significantly lower levels of PTSD symptoms following treatment than various control group members.

The review also uncovered some important caveats. Among them was the discovery that increased mindfulness following an intervention was not linked to fewer PTSD symptoms after treatment. Although this finding may have been the result of methodological problems in the research, it appears that becoming more mindful does not necessarily translate to experiencing less traumatic stress. 

The severity of PTSD symptoms at the onset of an intervention was also not related to changes in mindfulness or a reduction of symptoms following treatment. Those with and without a PTSD diagnosis responded similarly to mindfulness-based therapies.

Finally, although researchers anticipated that trauma-specific mindfulness-based interventions would outperform traditional programs like mindfulness-based stress reduction (MBSR), results from these programs have been found to be comparable, suggesting that mindfulness training on its own may be impactful.

Although these findings are encouraging, the review’s authors note of a potential source of bias known as the file drawer problem: the possible over-inflation of positive results that may occur when only studies with positive or significant statistical effects are published. It is important to not overlook the possibility that studies with negative outcomes are underreported or tossed out altogether.

Indeed, in recent years, contemplative scientists have called into question whether the negative or harmful effects of meditation have been suppressed in the research literature. This is of particular importance when considering the use of mindfulness-based therapies with those with a trauma history, for whom meditation and contemplation may exacerbate an already unstable nervous system. This thorny dilemma will require additional, high-quality studies to be resolved.

How Mindfulness-Based Therapies May Change Brain Structure

Brain imaging studies provide another promising research avenue that may inform our understanding of how mindfulness-based therapies aid in trauma recovery. In one study, 23 male Iraq and Afghanistan combat veterans were randomly assigned to either a Mindfulness-Based Exposure Therapy (MBET) group, which combines mindfulness with traditional exposure therapy, or a present-centered group therapy (PCGT), which encourages acceptance of thoughts and emotions as they occur in the present moment.

Functional magnetic resonance imaging (fMRI) brain scans performed before and after treatment showed that those receiving MBET had significantly more connections between the default mode network (DMN), which is associated with mind wandering and rumination, and the dorsolateral prefrontal cortex (DLPFC) and anterior cingulate cortex (ACC).

This implies that mindfulness training may enable those experiencing post-traumatic stress to be better able to inhibit or reduce the pernicious cycle of negative thoughts, feelings, and memories that accompany traumatic stress. MBET group participants also had fewer symptoms of post-traumatic stress, however, their symptom reduction was not significantly different from those in the PCGT group.

Findings from this study of veterans with PTSD parallel those conducted with adults without PTSD in which meditation has been found to benefit physical and mental health and change the structure and function of the DMN, amygdala, and hippocampus, affecting our impulses and decision-making.

Although many questions remain unanswered, including whether or not these brain changes translate to greater health, happiness, and well-being, they suggest that mindfulness may be beneficial for healing from adversity.