Psychogenic non-epileptic seizures

01OverviewDefinition, clinical context and the essential points that orientate the chapter.

Functional seizures are episodes of impaired awareness, responsiveness or movement generated by a disorder of nervous-system functioning rather than epileptic cortical discharges. They may involve shaking, collapse, motionless unresponsiveness or staring. Predisposing, precipitating and perpetuating factors differ substantially between people; trauma, anxiety or depression may be relevant for some but are neither universal nor required for diagnosis. Calling the events stress alone or saying tests are normal fails to provide a positive neurological formulation.

Semiology is interpreted probabilistically. Long duration, waxing and waning intensity, asynchronous or side-to-side movement, eye closure with resistance, retained recall or modulation by interaction can point towards a functional event. Yet syncope, frontal lobe seizures, movement disorders and sleep events can overlap. A clear smartphone video reviewed by an expert is often valuable. The strongest confirmatory test is simultaneous video-EEG capture of the person’s usual event with clinical features of a functional seizure and no corresponding epileptic activity, while acknowledging that some focal seizures are difficult to see on scalp EEG.

How the diagnosis is delivered affects engagement and outcome. The clinician should name it, show the positive features, explain what has been excluded and what may coexist, check understanding, and move immediately to a treatment pathway. The person should not be discharged from neurology merely because antiseizure medicine is unnecessary. Acute plans, medicine withdrawal and psychotherapy require individual specialist assessment and locally available FND services.

Key points

Psychogenic non-epileptic seizures are increasingly called functional or dissociative seizures because the events are genuine, involuntary manifestations of functional neurological disorder rather than deliberate behaviour.
Make the diagnosis from positive semiological features and specialist expertise, ideally capturing a typical habitual event on video-EEG without an epileptic ictal correlate when scalp EEG should detect one.
Prolonged fluctuating episodes, asynchronous limb movements, tightly closed eyes, variable responsiveness and recall can support functional seizures, but no single sign is diagnostic and frontal epilepsy can be unusual.
A normal routine interictal EEG does not prove functional seizures because many people with epilepsy have normal recordings between events.
Functional seizures and epilepsy can coexist; establish whether every reported event type has been characterised before withdrawing antiseizure medicine or altering emergency plans.
During a recognised typical event, keep the environment calm, protect from injury, avoid restraint and painful stimuli, and do not escalate repeated benzodiazepines when breathing and physiology are stable.
Explain the diagnosis directly: the episodes are real, common and potentially treatable, arise from altered nervous-system functioning, and are not fabricated or equivalent to structural brain damage.
Treatment begins with diagnostic understanding and may include seizure-warning and grounding strategies, FND-informed psychological therapy, occupational rehabilitation and treatment of relevant mood, trauma, sleep or pain disorders.
Antiseizure medicines do not treat functional seizures themselves; taper unnecessary therapy under neurological supervision after coexisting epilepsy has been sufficiently excluded.
Dissociative seizures are notifiable to DVLA and have their own current licensing standards, so driving advice remains necessary even after epilepsy is removed from the diagnosis.

02AetiologyUnderlying causes, associations and risk factors, with why each one matters.

Functional neurological vulnerability

Functional seizures arise from interacting attentional, arousal, learning and neurobiological factors rather than deliberate production or conscious simulation.

Physical or emotional precipitant

Illness, injury, panic, pain or adverse experience may precede onset, although no single stressor is required for diagnosis.

Coexisting epilepsy

Some people have both functional and epileptic seizures, which can shape expectations, emergency responses and symptom learning.

Maintaining factors

Fear, hypervigilance, avoidance, sleep disruption and repeated emergency treatment can reinforce attack networks after the original trigger has passed.

03PathophysiologyThe causal sequence from the underlying abnormality to symptoms and harm.

1
Altered threat and attention processing
Some models propose that internal sensations or contextual cues acquire excessive salience and trigger an involuntary defensive or dissociative state.
2
Loss of integrated control
Functional disruption of awareness, movement and autonomic control occurs without the hypersynchronous cortical discharge that defines an epileptic seizure.
3
Attack expression
The resulting episode can produce unresponsiveness, shaking, collapse or sensory change with variable duration and preserved physiological stability.
4
Reinforcement cycle
Alarm, avoidance and iatrogenic intervention can reinforce expectations of danger, increasing recurrence unless a credible rehabilitation model replaces them.

04Clinical features and red flagsSymptoms, examination findings, patterns of presentation and time-critical warnings.

Fluctuating motor event

A prolonged episode with pauses, changing intensity, asynchronous thrashing or side-to-side head movement can support functional seizure when the whole video and context are assessed by an experienced clinician.

Dissociative unresponsiveness

Motionless apparent unresponsiveness lasting many minutes, sometimes with partial recall or an escalating bodily warning, may represent a functional seizure rather than sleep, syncope or focal epilepsy.

Positive eye finding

Sustained eye closure during a convulsive-appearing event, particularly with resistance to opening, can add diagnostic weight but should never function as a solitary bedside test.

Possible coexisting epilepsyRed flag

A separate stereotyped brief event with lateralised onset, injury, postictal confusion or epileptiform evidence should be characterised independently rather than folded into the functional diagnosis.

Iatrogenic emergency patternRed flag

Repeated benzodiazepines, intubation or critical-care admission for prolonged stable events despite prior functional diagnosis signals the need for an accessible, specific emergency plan and staff education.

05InvestigationsWhat to request, why it matters and how to interpret it.

Investigation order

Read from the initial assessment onwards. Tests may run in parallel in urgent care; first-line, preferred, confirmatory, definitive and gold-standard labels appear only when the chapter explicitly states them.

01
Detailed event history and witness videoFirst step
Why
Identify positive functional features and determine whether more than one event phenotype exists.
Interpretation and limitations
Review onset, movement, eyes, responsiveness, duration, recovery and context without relying on one sign. Confirm that any recorded event is the person’s habitual episode before drawing conclusions.
02
Video-EEG capture of a typical event
Why
Establish electroclinical concordance and distinguish functional seizures from epileptic events when uncertainty persists.
Interpretation and limitations
Typical functional semiology without an ictal EEG change supports diagnosis when the suspected epileptic comparator should be scalp-visible. Expert interpretation is required because movement artefact and deep or focal seizures can complicate recording.
03
Routine EEG
Why
Support a separate epilepsy hypothesis or classification when clinically indicated.
Interpretation and limitations
A normal interictal result proves neither functional seizures nor absence of epilepsy, and incidental non-specific abnormalities should not perpetuate an epilepsy label without electroclinical evidence.
04
Neurological and mental health formulation
Why
Find coexisting neurological disease, dissociation, mood, trauma, pain, sleep and social factors relevant to treatment.
Interpretation and limitations
Assessment is collaborative rather than a search for one hidden psychological cause. Functional seizures can occur without a recognised trauma and alongside epilepsy or another neurological disorder.
05
Medication and emergency-care audit
Why
Identify unnecessary antiseizure exposure and previous rescue interventions that may be causing harm.
Interpretation and limitations
Reconcile all event types and original evidence before tapering. Review ambulance and emergency records for respiratory depression, repeated intubation and inconsistent plans that can be prevented through clear documentation.

06Differential diagnosisRealistic alternatives and the features that help distinguish them.

Epileptic seizure

Stereotyped onset, lateral tongue injury, postictal change and ictal EEG support epilepsy, although scalp recordings can miss selected focal seizures.

Convulsive syncope

Presyncope, pallor, a trigger and rapid recovery favour hypoperfusion; brief jerks are common during syncope and cerebral hypoperfusion.

Panic or dissociative episode

Prominent fear, hyperventilation and retained interaction may suggest panic, but functional seizures can include similar autonomic symptoms.

Movement or sleep disorder

Tics, dystonia, parasomnia and REM behaviour have characteristic timing, urge, posture or sleep-stage relationships during assessment.

07ManagementImmediate care, first-line treatment, alternatives and escalation.

01Acute eventProtect without escalating reflexivelyFirst stepEscalationA seizure-like event occurs in someone with suspected or documented functional seizures.

11. Assess airway, breathing, circulation, glucose, injury and pregnancy or new-neurology context, and compare the event with the documented habitual phenotype.
22. Remove hazards, cushion the head, maintain a calm low-stimulation environment, avoid restraint and painful stimulation, and observe breathing and recovery.
33. If the event is typical and physiology stable, avoid repeated benzodiazepines and intubation; use the agreed grounding or recovery plan when the person is receptive.
4Escalation4. Escalate normally for a new pattern, significant injury, hypoxia, metabolic abnormality, suspected epileptic status or failure to recover in the expected way.

02DiagnosisEstablish positive evidenceRecurrent seizure-like episodes remain unexplained or treatment-resistant.

11. Obtain separate descriptions and videos of every event type and review previous EEG, imaging, treatment response and emergency records.
22. Identify converging positive functional semiology while retaining syncope, epilepsy, sleep and movement disorders in the active comparison.
33. Arrange video-EEG capture of a habitual event when needed, ensuring the report states which phenotype was recorded and the confidence limits.
44. Decide explicitly whether epilepsy coexists and construct different acute and long-term plans for each event type if it does.

03RecoveryExplain and rehabilitateThe specialist has sufficient positive evidence for functional seizures.

11. Name the diagnosis respectfully, show the positive features, explain that symptoms are involuntary and potentially reversible, and invite questions or disagreement.
22. Provide a written formulation, reliable educational material and a tailored event plan for the person, family, ambulance and emergency teams.
33. Refer to an FND-informed multidisciplinary pathway, selecting psychological, occupational and physical approaches and treating relevant comorbidity through shared goals.
44. If epilepsy is excluded, taper antiseizure medicine with neurology supervision, review driving under DVLA rules and maintain follow-up to monitor outcome and diagnostic change.

Key medicines and prescribing safety2 treatments · regimens, roles and cautions

Avoids cognitive, mood, reproductive, bone and organ toxicity from a drug that cannot treat the functional mechanism and reinforces an accurate management plan.

No antiseizure medicine for functional seizures alone

There is no therapeutic antiseizure dose for functional seizures; when epilepsy has been sufficiently excluded, an epilepsy specialist should withdraw unnecessary medication gradually, usually one agent at a time on a medicine-specific schedule.

Never stop abruptly or taper before all event phenotypes and the original epilepsy evidence are reviewed. Some people have both conditions, and benzodiazepine or barbiturate withdrawal requires a particularly slow specialist schedule.

Reducing a coexisting symptom burden can improve engagement, daily function and vulnerability to attacks within a wider rehabilitation programme.

Medication for a defined comorbidity

Treat depression, anxiety, migraine, pain or sleep disorder using its own evidence-based regimen and careful titration; no antidepressant or analgesic should be presented as a direct cure for functional seizures.

Agree a named target and monitor response. Avoid sedative polypharmacy, opioid escalation and adverse interactions, and do not imply that prescribing proves a purely psychiatric cause.

08ComplicationsImportant consequences, why they occur and why they matter clinically.

Iatrogenic respiratory and traumatic harm

Repeated benzodiazepines, restraint and intubation can cause hypoventilation, aspiration and procedure injury during physiologically stable functional events.

Unnecessary antiseizure exposure

Misdiagnosis produces sedation, reproductive risk, interactions and monitoring without treating the functional mechanism during prolonged treatment.

Driving and occupational restriction

Unpredictable loss of control creates collision risk and work or financial consequences even after epilepsy has been confidently excluded.

Stigma and chronic disability

Disbelief and fragmented explanations worsen shame, avoidance, healthcare use and disengagement from effective rehabilitation over time.

09Monitoring and follow-upTreatment response, safety checks and longer-term review.

Track functional and any epileptic event types separately, including frequency, warning symptoms, duration, recovery, emergency attendance and injury.
Review understanding and acceptance of the diagnosis, because confusion such as ‘nothing is wrong’ predicts disengagement and repeated emergency investigation.
Monitor progress against functional goals—education, work, mobility, independence and reduced emergency treatment—not only whether every event has ceased.
During antiseizure taper, watch for emergence of a distinct stereotyped event and restore neurological review rather than automatically relabelling it functional or epileptic.
Reassess mood, trauma symptoms where relevant, self-harm risk, sleep, pain, safeguarding, driving and treatment access through coordinated follow-up.

10Special situationsVariants, exceptions and circumstances that change the usual approach.

Positive diagnosis changes care

Showing the observed features that support FND is more credible and safer than saying MRI and routine EEG were normal, because normal tests occur in epilepsy too.

Involuntary is explicit

Functional symptoms are not consciously produced; malingering and factitious disorder are different constructs and should not be insinuated through ambiguous language.

Event plans prevent harm

A concise description of the habitual event, expected duration and escalation triggers can reduce repeated benzodiazepines and intubation while preserving reassessment for genuine emergencies.

Coexistence requires two plans

When epilepsy and functional seizures both occur, family and emergency teams need distinguishing features and separate rescue thresholds rather than one generic seizure instruction.

Psychology is rehabilitation

FND-informed psychological treatment can address warning signals, attention, dissociation, avoidance and comorbidity even when no trauma or current stressor is identified.

11Common pitfallsFrequent interpretation and management errors.

01
Diagnosing functional seizures solely because routine EEG and MRI are normal mistakes absence of evidence for positive diagnostic evidence.
02
Administering escalating benzodiazepines to every prolonged stable habitual event can cause respiratory depression, intubation and intensive-care harm.
03
Telling a patient that episodes are just stress or all in the mind invalidates involuntary symptoms and offers no treatment mechanism.
04
Withdrawing all antiseizure medicine immediately after one functional event can expose unrecognised coexisting epilepsy and precipitate withdrawal seizures.
05
Ending neurological follow-up at diagnosis leaves communication, rehabilitation, driving, comorbidity and possible diagnostic evolution without clinical ownership.