Notes to accompany talk on 31st May 2026

Trauma, Memory, and Metabolising Experience

These resources explore how difficult or overwhelming experiences can become processed, integrated, or remain “stuck.” They include research papers, educational resources, and diving-specific explanations related to trauma, stress, and recovery.

Trevett, Peck and Forbes (2010)
Research exploring the psychological impact of scuba diving incidents, including how some divers continue to experience distress long after the physical event has ended. https://pubmed.ncbi.nlm.nih.gov/20159211/

My blog discussing the above study and how common psychological trauma is in scuba diving.

Discussion of Jennifer Hunt article on the Fit to Dive blog, DCI and shame, guilt and embarrassment.
Social reactions to decompression illness

More Fit to Dive blogs in the diving trauma category: Trauma – Fit To Dive

Kierney and Lanius: Nature Mental Health (2024)
A research paper exploring how traumatic experiences are stored and processed differently from ordinary memory, including the role of survival responses and fragmented memory systems. https://www.nature.com/articles/s44220-024-00324-z And a more readable summary: https://www.ruthlanius.com/autobiographical-memory

Default mode network https://www.mpg.de/7738341/brain-architecture-daydreaming; Original research https://www.sciencedirect.com/science/article/abs/pii/S1053811913010057?via%3Dihub

Psychology Today article on neurobiology of trauma: https://www.psychologytoday.com/gb/blog/relationship-and-trauma-insights/202603/how-trauma-hijacks-your-brain-and-how-emdr-can-help

Core PTSD Symptom Clusters (ICD-11)

These three clusters represent the core features of PTSD. At least one symptom from each cluster must be present for diagnosis.

• Re-experiencing in the “here and now”: The involuntary, intrusive re-living of the trauma through flashbacks or nightmares, accompanied by the feeling that the event is happening right now.
• Avoidance of traumatic reminders: Staying away from internal thoughts, feelings, or external reminders (people, places, or situations) associated with the trauma.
• Sense of current threat: A persistent, heightened perception of danger, characterized by hypervigilance or an exaggerated startle response.

DSM Criteria for PTSD: https://www.ptsd.va.gov/professional/treat/essentials/dsm5_ptsd.asp and https://www.mayoclinic.org/diseases-conditions/post-traumatic-stress-disorder/symptoms-causes/syc-20355967

ICD Criteria for PTSD: https://pmc.ncbi.nlm.nih.gov/articles/PMC5774423/

EMDR and Adaptive Processing

These resources provide information about EMDR (Eye Movement Desensitisation and Reprocessing), adaptive information processing, and how the brain may naturally process and integrate difficult experiences over time.

EMDR UK
General information about EMDR therapy, research, and accredited practitioners.
https://emdrassociation.org.uk/

How EMDR Works video
A visual explanation of how EMDR may support the processing and integration of difficult or traumatic experiences.

EMDR UK introductory EMDR video
An overview of EMDR provided by EMDR UK, including what EMDR is and how it is used.

My colleague also wrote a helpful article for people thinking of receiving EMDR: How does EMDR Really Work

And this article was written for medical professionals: to explain EMDR.

Theories and Models Proposed to Explain How EMDR Works

(In all honesty, we don’t fully understand it yet, what we do know is”it’s weird, but it works”.)

Adaptive Information Processing (AIP) Model

This is the main theoretical model behind EMDR, developed by Francine Shapiro. The idea is that the brain normally processes and integrates experiences into adaptive memory networks. Under overwhelming stress or trauma, this processing may become disrupted, leaving memories stored in a fragmented, emotionally intense, and state-dependent way. EMDR is proposed to help restart or facilitate adaptive processing so that experiences become more integrated and less distressing.

Working Memory Theory

One of the strongest experimentally supported explanations. Holding a distressing image or memory in mind while simultaneously engaging in bilateral stimulation (such as eye movements) places demand on working memory. Because working memory has limited capacity, the memory may become less vivid and less emotionally intense when recalled repeatedly in this way. (Basically, we use cognitive loading to tax the brain and this seems to help it allow the “paused” distressing memory to process more slowly and sort of “diluted”.)

Orienting Response

Bilateral stimulation may trigger an orienting response: a natural attentional reflex linked to scanning, investigating, and determining safety. Once no threat is detected, this may shift the nervous system toward settling and regulation, making it easier to process difficult material without becoming overwhelmed. (We say “one foot in the past and one in the present” so that the person can find the feeling of safety in the present, while allowing the distress of the past memory as it processes).

Using EMDR to improve diving performance: https://www.fittodive.org/products/digital_downloads/information-about-emdr-coaching-for-scuba-divers

EMDR Services for divers: https://www.fittodive.org/pages/services

Panic, Regulation, and Recovery

These resources focus on panic, stress responses, emotional regulation, and recovery after difficult experiences.

Free Panic Triangle eGuide and video
An introductory guide and video resource explaining the Panic Triangle concept.
https://www.fittodive.org/courses/panic-triangle-eguide

Prevent Panic in Scuba Diving
A more in-depth educational course exploring panic, stress responses, readiness, and psychological skills in diving.
https://www.fittodive.org/courses/prevent-panic-in-scuba-diving

Window of Tolerance video
An explanation of regulation, overwhelm, and how people move between different states of arousal and functioning. https://www.youtube.com/watch?v=6nu3iqI8Idc

Emotion Regulation Video

Feelings Wave Video

And there is more on trauma and diving than I could fit into the talk in the “Talk Trauma in Scuba Diving” course. https://www.fittodive.org/courses/talk-trauma-in-scuba-diving

Practices and Things You Can Do

This section contains practical tools, exercises, and approaches that may help with grounding, recovery, reflection, and emotional regulation.

Help After a Scuba Diving Accident or Incident
Information and support options following a distressing or traumatic dive experience.
https://www.fittodive.org/pages/dive-trauma-resource-index

Free Audio Practices for regulation and safety https://www.fittodive.org/pages/practices-for-divers

Take Away Ideas

0. Re-establish safety first
   If somebody has been through something distressing or potentially traumatic, the first priority is safety. That might mean warmth, shelter, hydration, medical care, getting out of the environment, or simply getting somewhere calmer and more settled – home if approriate. It also includes psychological safety: being around people who are supportive, calm, non-judgemental, and able to help somebody feel connected and contained rather than overwhelmed. Very often the nervous system cannot begin properly processing experience until there is at least some sense of present safety. One of the difficulties after distressing events is that people often keep pushing on, analysing, suppressing, or trying to carry on as normal because slowing down can feel difficult or unsafe in itself. But creating enough safety and stability for the nervous system to settle is often the first step in allowing experience to move through and process adaptively. This is also where psychological first aid can be really valuable: recognising distress, listening, helping somebody feel supported, and linking them with appropriate help and resources if needed. DAN have free elearning on this too https://dan.org/dan-launches-surface-support-course/ (and like First Aid … the time to learn it is before you need it.)
1. Allow some space for the experience to process
   After a difficult or stressful dive, many people immediately move into analysing, distracting, suppressing, or trying to “fix” how they/you feel. Sometimes the nervous system simply needs a bit of space to begin sorting through what happened. Reflection, quiet time, rest, and slowing down can help information start moving through rather than remaining stuck. Note also though, that when things slow down, and you get some space, this is when the brain’s default mode network activates, and its normal to notice thoughts like “Its my/their fault”, “If Only …. ” “Did I do enough?”. This is a normal part of processing, so try and let it run without getting dragged into it.
2. Stay connected to present safety
   One of the key problems in trauma is that past and present collapse together. Grounding back into the present helps the nervous system recognise that the event is over. That might involve noticing the environment, breathing, connection with other people, physical sensations, or simply orienting to where you are now.
3. Allow emotions and images to move through rather than constantly blocking them
   Intrusive thoughts, images, or strong emotions are often the nervous system attempting to process experience. If it feels manageable and safe enough, it can help to allow these reactions to come and go without immediately fighting them or pushing them away. The aim is not becoming overwhelmed by them, but also not endlessly defending against them. Adding a slightly stimulating activity, like listening to music, binaural beats or playing a simple block builder type computer game could help offer something to focus on.
4. Notice defensive reactions early
   Blame, anger, rigidity, shame, avoidance, over-analysis, and defensiveness are often signs that something emotionally important has been activated. Noticing these reactions in smaller everyday situations can help people recognise where old unresolved material may already be sitting in the system.
5. Practice reflection
   Talking through experiences in a psychologically safe environment can help information become more coherent and integrated. A practice of shared reflection, debriefing, can provide the opportunity to build perspective, gain feedback and notice what still feels stressful or unclear. Debriefs that focus on learning can help individuals process experience, absorb learning, and notice lessons.
6. Using dive logs or journalling
   Logbooks can become more than records of depth and time. They can help divers notice emotional responses, learning, uncertainty, decision-making, what helped, and what they would do differently next time. That process supports adaptation and helps experiences move into more organised adaptive memory.
7. Build readiness and competence
   Skills, preparation, rescue training, and familiarity reduce helplessness. The greater somebody’s ability to cope with a situation, the less likely the nervous system is to experience it as overwhelming or traumatic. Readiness is protective both physically and psychologically.
8. Develop regulation skills before they are needed
   Attention regulation, grounding, emotional regulation, and self-compassion are trainable skills. The more familiar somebody becomes with returning attention to the present, sitting with stress responses, and reconnecting with useful task focus, the more capacity they have available under pressure. Acquiring these skills also can offer an escape from ego-defenses (over-analysing, avoidance, blame etc.)
9. Use ordinary regulating activities
   Processing does not only happen through talking. Walking, hobbies, gardening, movement, being outdoors, scanning the environment, social connection, and time in nature can all help the nervous system settle and process experience more effectively. This can help the brain move into the “task positive network” or present sensory experience, and reduce the rumination and worry loops that can build in the default mode network. (Diving is often a great way to engage the task positive network … just not always a good idea if there is unprocessed trauma that could be triggered by things like: being underwater, the sound of the regulator, a certain dive site, .. or any of the sensory aspects of diving.)
10. Seek support before things become deeply stuck
    Sometimes experiences do not move through on their own. If reactions remain intense, persistent, or begin affecting diving, relationships, sleep, mood, or functioning, professional support may help the nervous system process what has become stuck. Continuing to dive on a psychological injury may risk entrenching the problem, as would running on a broken leg! If possible, address the injury, then rehabilitate. Early support can also help prevent new experiences attaching onto older unresolved material.