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Functional/Dissociative Seizures (PNES)

Functional/dissociative seizures (FDS), long known as psychogenic nonepileptic seizures (PNES), were involuntary episodes that resembled epileptic seizures, syncope, or other paroxysmal events but did not arise from the epileptic electrical activity that defined epilepsy. They were a form of functional neurological disorder and could affect awareness, responsiveness, movement, sensation, cognition, and autonomic function.

Overview

FDS were real events, not deliberate simulation, malingering, or factitious behavior. They could include convulsive-looking movement, collapse, staring, sensory change, speech interruption, or prolonged unresponsiveness. A person could have functional seizures, epileptic seizures, syncope, or more than one of those conditions; one diagnosis did not exclude the others.

The disorder had no single psychological profile or universal trigger. Adverse experiences, illness, injury, chronic stress, psychiatric conditions, and dissociation could contribute to an individual’s vulnerability, precipitation, or persistence of events, but none was required for diagnosis. The functional-seizure diagnosis rested on positive clinical evidence rather than the discovery of trauma or the absence of structural findings alone.

Terminology and Classification

The label ‘’psychogenic nonepileptic seizures’’ remained familiar in records, patient communities, and older research, but each part of the phrase carried limitations. ‘’Psychogenic’’ could imply a single psychological cause that had not been established for every person; ‘’nonepileptic’’ defined the events by what they were not. ‘’Pseudoseizure’’ was inaccurate and stigmatizing because it suggested falsity.

In 2025, an International League Against Epilepsy task force proposed ‘’functional/dissociative seizures’’ and the abbreviation FDS as a flexible international label. ‘’Functional seizures’’ aligned with functional neurological disorder, while ‘’dissociative seizures’’ aligned with ICD-11 classification and fit some people’s experience more closely. The American Academy of Neurology’s December 2025 guideline used ‘’functional seizures’‘. Individual preference and clinical context still shaped which current term a person used.

Under DSM-5-TR, these episodes fell within functional neurological symptom disorder with attacks or seizures. ICD-11 placed them within dissociative neurological symptom disorder. Neither classification made intentional production part of the diagnosis.

Causes and Associated Factors

FDS were understood through a biopsychosocial model rather than one linear cause. Predisposing vulnerabilities, immediate precipitants, and factors that maintained episodes could differ within the same person and could change over time. Physical illness, pain, sleep loss, injury, sensory overload, interpersonal threat, shame, trauma reminders, and sustained physiological arousal could all form part of an individual’s pattern without becoming universal explanations.

Psychiatric conditions and adverse life experiences occurred frequently in clinical populations, but they were not universal and were not required diagnostic criteria. A clinician therefore could not infer abuse, trauma, family conflict, or psychiatric illness from functional seizures alone.

Functional seizures did not protect a person from epilepsy. Evaluation had to distinguish each recurring event type because antiseizure treatment appropriate for epilepsy did not treat FDS, while mislabeling an epileptic or physiological event as functional could delay urgent care.

Symptoms and Presentation

FDS presentation varied widely. Motor events could involve shaking, stiffening, variable or asynchronous limb movement, side-to-side head movement, or waxing-and-waning intensity. Nonmotor events could involve staring, collapse, loss of responsiveness, sensory change, altered awareness, or a sleep-like appearance. Some people had more than one presentation.

Certain features, including sustained eye closure, mismatched or variable movement, a fluctuating course, or partial responsiveness, could raise clinical suspicion. No single sign proved the diagnosis, and epileptic seizures could also present without generalized convulsions. Recovery ranged from rapid orientation to prolonged fatigue, speech difficulty, confusion, pain, or emotional vulnerability.

Diagnosis and Differential Diagnosis

Diagnosis began with a detailed description from the person and witnesses, including the onset, context, sequence, duration, awareness, movement, breathing, injuries, and recovery. Smartphone recordings reviewed by an experienced clinician could add useful semiological evidence.

Video EEG that captured a person’s typical event without a corresponding epileptic discharge supported a documented diagnosis and remained especially valuable when events were frequent enough to record. A normal routine EEG between events did not establish FDS, and failure to see an ictal discharge during an event required interpretation in light of the seizure type and recording quality. When a person had more than one event pattern, clinicians attempted to characterize each typical pattern rather than assuming one captured event explained them all.

Differential diagnosis included epileptic seizures, syncope and cardiac rhythm disturbance, sleep disorders, migraine, movement disorders, panic, metabolic disturbance, medication or substance effects, and other functional neurological symptoms. When an event resembled syncope, ECG monitoring, orthostatic assessment, or tilt-table testing could complement neurological evaluation. Assessment also included co-occurring epilepsy, psychiatric conditions, and medical illnesses without treating any one of them as proof of causation.

Treatment and Management

Effective care began with a clear diagnostic name, a respectful explanation of the positive evidence, and continued clinical follow-up. The diagnosis was not delivered as “nothing is wrong,” and referral to psychological treatment did not end neurological responsibility.

The 2025 American Academy of Neurology guideline found that studied psychological interventions were possibly effective in reducing event frequency, improving the chance of event freedom, reducing anxiety, and improving quality of life or psychosocial function. Approaches included functional-seizure-specific cognitive behavioral therapy, neurobehavioral therapy, Retraining and Control Therapy, and other structured interventions. Treatment was individualized to the person’s event pattern, goals, co-occurring conditions, access, and willingness; no one therapy or trauma narrative applied to everyone.

Education, trigger and warning-sign recognition, event plans, rehabilitation, sleep and pain care, and treatment of co-occurring psychiatric or medical conditions could all be part of management. Family, caregivers, or other chosen supporters could participate with the person’s consent.

Antiseizure medications and benzodiazepines did not treat FDS and could cause harm when used without epilepsy or another indication. A clinician supervised any taper because a person might have co-occurring epilepsy, another reason for the medication, or withdrawal risk.

Event Safety and Acute Care

During a familiar event, supporters protected the person from falls or nearby hazards, avoided restraint and objects in the mouth, kept the environment calm, and followed the person’s individualized plan. Some people benefited from quiet orientation or reassurance; others needed less speech or touch. Painful stimulation and attempts to force responsiveness could intensify distress or cause injury.

A functional-seizure diagnosis did not make every future event benign or interchangeable. A first or unfamiliar event, a materially different presentation, significant injury, breathing difficulty, pregnancy-related concern, suspected poisoning or metabolic crisis, prolonged failure to return toward the person’s baseline, or uncertainty about concurrent epilepsy or another acute illness required appropriate emergency assessment.

Course and Prognosis

Course varied. Some people became event-free, some had fewer or less disabling events, and others continued to experience substantial disability. Earlier accurate diagnosis, a usable explanation, therapeutic engagement, continuity of care, and access to appropriate treatment could improve the path forward, but none guaranteed a particular outcome.

Delayed recognition exposed people to unnecessary antiseizure medication, repeated emergency intervention, loss of driving or employment, educational disruption, and stigma. Functional seizures themselves were not epileptic status, but falls, aspiration risk from a separate illness, medication effects, or an incorrectly assumed diagnosis could still create medical danger.

Historical Context and Medical Evolution

Older descriptions of seizure-like events without recognized epilepsy became entangled with the diagnosis of “hysteria,” a gendered framework used to dismiss or institutionalize people whose symptoms did not fit available structural explanations. Nineteenth-century neurological study, including Jean-Martin Charcot’s work, treated the events as worthy of clinical observation but still relied on concepts and demonstrations later criticized for suggestion and spectacle.

Twentieth-century “conversion” theories shifted attention toward unconscious psychological conflict. That model recognized involuntary symptoms but often encouraged a false binary between neurological and psychological illness. DSM-5 removed the requirement to identify a psychological stressor and emphasized examination findings incompatible with recognized neurological disease.

By 2025 and 2026, professional guidance emphasized positive diagnosis, nonstigmatizing terminology, assessment for co-occurring epilepsy and psychiatric conditions, shared decision-making, continued neurological care, and evidence-based psychological intervention when appropriate.

Associated Character: Charlie Rivera

Main article: Charlie Rivera

Charlie’s first functional/dissociative seizure occurred in late November 2027, during his junior year at Juilliard. He had just experienced iatrogenic harm from a therapist who described his disability-related reliance on Logan Weston as toxic and predicted that Logan would leave. Charlie tried to withdraw from his support system, collapsed outside a CVS after leaving the appointment, and deteriorated over the following days through repeated syncope, vomiting, undernutrition, exhaustion, pain, shame, and emotional withdrawal.

The first FDS event occurred at the apartment before his admission to Mount Sinai Hospital. Logan, Ezra Cruz, Riley Mercer, Jacob Keller, and Peter Liu were present. Logan considered a functional seizure; Julia Weston, speaking by phone, directly asked whether PNES had been considered and told him to take Charlie to the hospital. Ezra drove while Logan and Riley supported Charlie in the back seat, and Charlie retched violently before they reached Mount Sinai.

During the subsequent two-week admission, video EEG documented Charlie’s typical events without epileptic activity. The neurological findings and Dr. N. Lanier’s evaluation were used together rather than treating the prior therapy trauma as a substitute for neurological evidence. Lanier documented severe internalized guilt, medical trauma, emerging depressive features, and the specific iatrogenic harm that had intensified the crisis. Charlie did not have epilepsy.

The admission also established POTS and gastroparesis. Severe fatigue and post-exertional illness were already part of his life, but his ME/CFS diagnosis came in 2029 rather than during the 2027 hospitalization.

Charlie’s Event Pattern

Charlie’s later-established FDS presentation was primarily nonmotor and dissociative. Onset was more gradual than his usual syncope: his gaze lost focus, his responsiveness narrowed, and his eyes closed as he became limp. Small hand tremors, eyelid fluttering, or repetitive movement could occur, but generalized convulsive movement was not his usual functional-seizure pattern. When someone cradled him, he could look as though he had fallen asleep despite the acute distress that preceded the event.

His functional seizures lasted minutes rather than the brief interval typical of his familiar faints. He surfaced slowly, sometimes opening his eyes before he could focus, orient, recognize the room, or speak. Speech could lag behind other responses without becoming the separate aphasia pattern documented later in his life. Fatigue and reduced emotional defenses could continue for hours.

Logan distinguished established patterns through context, timing, Charlie’s appearance, and the recovery course rather than one heart-rate or blood-pressure value. Charlie’s familiar syncope was associated with vasovagal susceptibility and episodic orthostatic hypotension. It was usually tied to upright posture, heat, dehydration, exertion, or inadequate intake and improved after he was safely horizontal; his POTS contributed chronic orthostatic tachycardia and presyncope but did not automatically explain every faint. His functional seizures more often followed sustained emotional overload, trauma reminders, shame, sensory strain, or a feeling of being trapped, although pain, sleep loss, hunger, and autonomic symptoms could compound the same event. When the pattern was unclear or medically different, Logan treated uncertainty as a reason to assess for concurrent illness rather than assuming FDS.

Support and Recurrence

During a familiar event, Logan kept Charlie physically safe, lowered stimulation, monitored for signs of a separate medical crisis, and used quiet orientation: “You’re home. You’re safe. I’m here. Take your time.” He did not shake Charlie, demand immediate speech, or force him to explain the trigger during recovery.

Episodes recurred after 2027 during periods of extreme combined stress. Public ableism and body-shaming could become a trigger when Charlie felt unable to escape or correct what strangers said about him. During one later crisis after he read an ableist online thread, Ezra’s protective anger initially intensified Charlie’s shame; Ezra stepped back, Logan took over, and Charlie’s distress became speakable only after a functional seizure and its slow recovery.

Charlie received disability-informed psychotherapy and coordinated neurological care. Managing dehydration, undernutrition, pain, sleep disruption, sensory overload, and his other conditions reduced the physiological burden around potential events without recasting FDS as a direct symptom of POTS, gastroparesis, ME/CFS, or hEDS.

Daily Life and Accessibility

Useful access included permission to lie down safely, a low-stimulation recovery space, schedule flexibility, trusted support people, an individualized event plan, and time before speech or decision-making was required. People around Charlie learned that a familiar sleep-like event still required protection and observation and that delayed speech during recovery did not justify speaking about him as though he were absent.

FDS and POTS both produced collapse or unresponsiveness in Charlie, so his care plans documented the features and response associated with each known pattern. Staff and companions still evaluated injury, breathing, hydration, glucose, medication effects, and any new neurological signs rather than using the functional diagnosis to dismiss physical illness.

Medical-System and Public Context

Functional seizures carried a high risk of stigma because clinicians and bystanders could mistake “not epileptic” for “not real.” Misdiagnosis could lead either to unnecessary antiseizure treatment or to dangerous dismissal of a different acute event. Respectful care required both avoiding unnecessary emergency escalation for a familiar functional event and refusing to let the label overshadow new symptoms.

Charlie’s earlier medical invalidation, Puerto Rican identity, and visible disability shaped how readily his reports were believed. Dr. Lanier’s care mattered because she named iatrogenic harm without making Charlie’s interdependence, queerness, chronic illness, or need for support into pathology.

Sources

Medical Conditions Neurological Conditions Functional Neurological Disorders Charlie Rivera