Dissociation: Derealisation, Depersonalisation and Time Gaps

Dissociation is a break in the normally seamless flow of experience: perception, sense of self, time and memory stop running together for a second — or for an hour. From the inside it gets described as "everything went unreal", "I am not quite here", "I am watching myself from outside", "I drove home and cannot recall how". The word sounds clinical, so the first thing worth removing is the main fear: this is not the start of madness and not rare exotica.

What dissociation is and how common it is

The systematic review by Hunter et al. (2004) pooled prevalence data: brief derealisation and depersonalisation symptoms in the general population were reported by 26–74% of people over a lifetime, and by 31–66% at the time of a traumatic event. The clinically significant, persistent form is far rarer: population surveys using diagnostic interviews give 1.2–1.7% one-month prevalence in a UK sample and 2.4% current prevalence in a Canadian one. In clinical groups the numbers are higher — around 30% among war veterans with PTSD.

The working conclusion: catching yourself in a moment of unreality diagnoses nothing. What matters is duration, frequency and cost — how much it interferes with working, driving, being with people.

The spectrum: from zoning out on the road to severe forms

It helps to hold a scale in mind rather than a switch.

• The everyday end. Missing a turn on autopilot, drifting off in a long lecture, reading so deeply that noise stops registering. That is attention working normally.
• A stress response. During a very hard event perception narrows, sound recedes, time runs oddly, pain feels muted. That is a protective mode, not weakness.
• A persistent background. A sense of glass between yourself and the world for weeks, muted emotions, familiar faces looking unfamiliar.
• Severe forms. Time gaps with no account of your own actions, the body feeling like someone else's, a break in the sense of continuity of self. This route is separate and belongs in person with a clinician.

The key point: the closer to the right-hand end, the less this is a matter of self-help and the sooner a specialist is needed.

Derealisation and depersonalisation: the difference

These are constantly mixed up, though the distinction is simple — where the sense of unreality points.

Derealisation is about the external world. The room looks like a stage set, colours flatten, sounds arrive through cotton wool, a familiar street looks unfamiliar, distances seem wrong.

Depersonalisation is about the self. Your own voice sounds foreign, your hands do not feel like yours, emotions register as descriptions of emotions, and you observe yourself like a character in a film.

They often occur together, which is why diagnostic categories group them. Their crucial shared feature is preserved insight: the person knows the world has not changed, the perception of it has. That is the boundary with psychosis.

Why this is not going mad

Three things usually take the panic out of the subject.

First, dissociation is a mechanism, not a fault. When load exceeds what can be carried, part of the experience switches off — the same way acute fear switches off pain. The same mechanism at the other end of the spectrum is described in the article on the fight, flight and freeze responses: freezing and switching off are relatives.

Second, the fear "I am losing my mind" maintains the episode. Attention turns inward to check — "is this real right now?" — and the checking intensifies the sensation. The loop closes.

Third, episodes end. Even long states fluctuate rather than rise in a straight line.

Dissociation and trauma: what the data show

Dissociation holds a specific place in the traumatic picture. Lanius et al. (2010) described a dissociative subtype of PTSD: in some people the response runs not through being flooded but through excessive dampening — emotional detachment, derealisation and depersonalisation. On that basis the dissociative subtype was later included in DSM-5.

The second observation matters more for prolonged trauma. In a clinical sample (Hyland et al., 2020, N = 106) dissociative experiences were stronger in people matching the CPTSD picture than the PTSD picture — effect size d = 1.04 — and stronger still compared with those who matched neither (d = 1.44). Of the six clusters, dissociation was most associated with affective dysregulation (β = 0.33), re-experiencing in the here and now (β = 0.24) and disturbed relationships (β = 0.22). What those clusters are is covered in the article on complex PTSD; the general frame is in the account of what PTSD is.

And third: dissociation is not the same as an event returning into the present. That separate mechanism is covered in the article on flashbacks, and what the body does meanwhile is in The body keeps the score.

Stabilisation first, memory work later

This is the main practical point of the subject. With pronounced dissociation, help does not start with memories but with safety and skills: a stable routine, the ability to come back to the present, recognising your own early signs, a plan for when it hits. Only after that comes work with memory itself.

The ISTSS expert survey (Cloitre et al., 2011) found 84% of specialists endorsing a phase-based, sequenced approach for complex PTSD, with interventions matched to specific symptom sets; first-line interventions named there were emotion regulation strategies, narration of the trauma memory, cognitive restructuring, anxiety and stress management, and interpersonal skills.

An honest caveat: whether the phase is obligatory is debated. In a randomised trial, van Vliet et al. (2023) compared a phase-based approach (STAIR skills training followed by EMDR, n = 57) with immediate trauma-focused work (EMDR only, n = 64) in people with PTSD following childhood abuse: complex PTSD symptoms did not moderate the difference in outcomes, and the authors concluded that immediate trauma-focused treatment is a safe and effective option. They also state plainly that the predictive influence of dissociative sequelae needs further research.

One practical conclusion follows, and it is a dull one: the order is set by a clinician on the basis of your state, not by an article or a social media post. But if you are asked to retell the event in detail while you are regularly switching off, that is a good reason to ask how the plan is built and what happens if things get worse.

When it is not trauma

A sense of unreality is non-specific, and it has many explanations.

• Depression. Produces muting and detachment, but without a traumatic core — no intrusions, no avoidance of reminders, no sense of current threat.
• Long-running exhaustion. At the bottom of the tank, the glass between self and world appears in people with no traumatic history at all.
• Anxiety disorder. Derealisation is a frequent companion of panic attacks; there it is tied to the attack rather than to reminders.
• A borderline pattern. Dissociation occurs here too, but the leading themes are instability of self-image and fear of abandonment.
• ADHD and autism. Dropping out of a conversation and shutting down under overload run evenly from childhood and are explained by how attention and sensory processing are built.
• Bodily and external causes. Sleep debt, migraine, a panic attack, dehydration, cannabis, alcohol withdrawal, medication side effects. Add a shifted TSH, low ferritin and lack of vitamin B12, which produce brain fog and a stunned quality. Results you already have, the service will help you read.

Separately and without qualification: if the sense of unreality appeared suddenly and for the first time and comes with headache, disturbed speech or vision, weakness in the limbs or loss of consciousness, this is not a psychology topic — it is emergency care.

What helps you come back to the present

During an episode the task is not to work out the causes but to increase the number of signals saying "I am here, now".

• Footing and contact. Stand up, feel your feet, press your palms to a cool surface, hold something with pronounced texture.
• Five senses. Name five objects around you out loud, four sounds, three smells. Out loud works better than silently.
• Temperature. Cold water on the wrists and face is a fast, reliable entrance into the present.
• Movement. Walk, change posture, stretch. Dissociation likes stillness.
• Do not check reality. The question "is this definitely real?" amplifies the episode. Better to send attention outward — to a task, an object, a conversation.
• Routine. Sleep and food reduce episode frequency more noticeably than any in-the-moment exercise.

If you want to see where all this adds up, there are two different instruments. The free PCL-5 scale is a screener for PTSD symptoms: one axis, one score. The paid complex PTSD test separates the traumatic core from disturbances in self-organisation across six clusters and looks separately at the cost in work, relationships and daily life. Neither is a diagnosis.

If things are hard right now — thoughts of not living, a pull to hurt yourself, episodes with loss of control, or ongoing danger — in the US call or text 988 (Suicide and Crisis Lifeline); in the UK, Samaritans on 116 123; elsewhere, your local emergency number.

This article is informational and does not diagnose. It does not claim that you have a dissociative disorder, nor that you do not: that is determined by a clinician in person.