What Is Trauma?

Trauma results from experiences that overwhelm a person’s capacity to cope, leaving lasting effects on their emotional, psychological, and physiological functioning. Not every difficult experience is traumatic, and trauma responses depend heavily on the individual’s context, prior history, available support, and neurobiological makeup. Two people can live through the same event and respond very differently.

Clinicians commonly distinguish between two broad categories. Single-incident trauma (sometimes called Type I trauma) refers to a specific, bounded event such as a road traffic accident, a one-off assault, or a natural disaster. Complex or developmental trauma (Type II) involves repeated, prolonged experiences – typically in childhood and often within caregiving relationships – such as chronic abuse, neglect, domestic violence, or emotional unavailability from a primary carer. Complex trauma tends to have wider-reaching effects on identity, self-worth, relationships, and emotion regulation than single-incident trauma.

The Neuroscience of Trauma

Understanding what happens in the brain and body during and after trauma helps counsellors respond more effectively and communicate with clients in ways that reduce shame. Three concepts are especially useful in practice.

The window of tolerance is a term introduced by Daniel Siegel to describe the zone of arousal within which a person can process experience effectively – feeling present, able to think and feel simultaneously. When overwhelmed, a person moves into hyperarousal (panic, rage, flashbacks) or hypoarousal (numbness, dissociation, shutdown). A key goal of trauma-informed work is to help clients expand and return to this window.

Polyvagal theory, developed by Stephen Porges, provides a neurobiological account of how the autonomic nervous system responds to perceived threat. Porges described a hierarchy of responses: social engagement (the preferred, evolutionarily newest system), sympathetic activation (fight or flight), and dorsal vagal shutdown (freeze, collapse, dissociation). Understanding that freeze and shutdown are involuntary survival responses – not weakness or choice – can be profoundly relieving for clients who have blamed themselves for not “fighting back.”

Bessel van der Kolk’s work, particularly his book The Body Keeps the Score (2014), brought wide attention to the embodied nature of trauma. Van der Kolk argues that trauma is stored in the body, not just the mind, and that effective treatment often needs to engage somatic (body-based) experience rather than relying solely on verbal processing.

PTSD and Complex PTSD in ICD-11

Post-traumatic stress disorder (PTSD) is characterised by re-experiencing (flashbacks, nightmares), avoidance of trauma-related cues, and a persistent sense of current threat. The ICD-11, published by the World Health Organization, introduced Complex PTSD (CPTSD) as a distinct diagnosis. In addition to the core PTSD symptoms, CPTSD includes disturbances in self-organisation: affect dysregulation (difficulty managing emotions), negative self-concept (deep shame, worthlessness), and disturbances in relationships (difficulty trusting others, feeling permanently different).

Counsellors are not diagnosticians, but familiarity with these frameworks helps them understand client presentations and make informed referrals when specialist trauma treatment is needed.

Trauma-Informed Principles

The Substance Abuse and Mental Health Services Administration (SAMHSA) in the United States identified six key principles of trauma-informed care, which have been widely adopted in UK mental health and counselling settings:

• Safety – creating physical and emotional environments where clients feel secure.
• Trustworthiness and transparency – being clear about how the work operates, maintaining consistent boundaries, and explaining decisions.
• Choice – offering options wherever possible, returning a sense of control to clients who may have had control stripped from them.
• Collaboration – working with the client rather than doing things to them; the therapeutic relationship is a partnership.
• Empowerment – recognising and building on strengths, helping clients develop their own resources and capacities.
• Cultural, historical, and gender considerations – recognising how identity, power, and context intersect with trauma.

Adapting Counselling Practice

Trauma-informed counsellors adapt their approach from the first contact. This includes: explaining what will happen in sessions before it happens; offering grounding exercises when clients become dysregulated; pacing sessions to avoid overwhelming the client; remaining alert to non-verbal signs of dissociation; and not pressing for detailed trauma narratives before the client is ready or the therapeutic relationship is strong enough to hold them.

Judith Herman’s landmark work Trauma and Recovery (1992) described a three-phase model – safety, mourning, and reconnection – that remains highly relevant. Herman argued that safety must be established before any trauma processing begins, and that moving too quickly into traumatic material without adequate stabilisation can cause harm rather than healing.

Ethical Considerations

Trauma-informed practice requires counsellors to reflect honestly on their own competence. Working directly with trauma – particularly complex or developmental trauma – requires specialist training beyond a foundation-level qualification. The BACP Ethical Framework (2018) is clear that practitioners must work within their competence and seek supervision for work that approaches its edges. A trauma-informed stance does not mean every counsellor treats PTSD; it means every counsellor avoids inadvertently causing harm through ignorance of trauma’s effects.