Synonyms: the use of the terms hysterical seizures or pseudoseizures is now considered to be inappropriate.

Non-epileptic seizures (NES) is a descriptive term for a diverse group of disorders which refers to paroxysmal events that can be mistaken for epilepsy, but are not due to an epileptic disorder. There are two sub-categories of NES:

• Physiological: includes a broad spectrum of disorders, e.g. syncope, paroxysms of acute neurological insults, paroxysmal toxic phenomena, non-toxic organic hallucinosis, non-epileptic myoclonus, sleep disorders, paroxysmal movement disorders, paroxysmal endocrine disturbances and transient ischaemic attacks (TIAs).
• Psychogenic seizures include different types:¹
  • Dissociative seizures are involuntary and happen unconsciously. This is the most common type of NES and the person has no control over the seizures.
  • Associated with psychiatric conditions that cause seizures, e.g. panic attacks.
  • Factitious seizures: seizures are consciously or deliberately ‘put on’, e.g. Münchhausen's syndrome.

Epidemiology

• The true prevalence is unknown.
• Up to one fifth of patients who present to specialist clinics with seizures do not have epilepsy. The majority of such patients suffer from psychologically mediated episodes (dissociative seizures).
• Up to one in five patients with apparently intractable epilepsy referred to specialist centres is found to have no organic cause for their seizures.²
• Adult studies have shown a 4:1 female:male ratio for psychogenic non-epileptic seizures.
• One study found that the psychological factors relevant to the development and maintenance of NES included anxiety or stress, physical abuse, significant bereavement, family dysfunctioning, relationship problems, depression and sexual abuse.³

Presentation

• It can be difficult to differentiate NES from epilepsy, especially as the two disorders co-exist in up to 30% of patients.
• Epileptic and non-epileptic seizures can look the same and have the same features:¹
  • Can happen suddenly and without warning
  • Can include a loss of awareness or the person becomes unresponsive, makes strange or repeated movements, or convulses
  • Can both cause injury and urinary incontinence
  • Can both happen when awake and during sleep
• It is essential to make a thorough assessment and ensure no further harm is caused by inappropriate diagnosis and treatment.
• Features suggesting NES include: duration over two minutes, gradual onset, fluctuating course, violent thrashing movements, side to side head movement, asynchronous movements, eyes closed and recall for period of unresponsiveness.
• Features suggesting epilepsy include automatisms, incontinence and biting the tongue.

Differential diagnosis of epilepsy²

• Medical causes of transient neurological dysfunction (with or without loss of consciousness)
  • Syncope: vasovagal, cardiogenic
  • Neurological: cerebrovascular, migraine, vertigo, cataplexy, parasomnias, movement disorders, startle-induced phenomena
  • Endocrine and metabolic: hypoglycaemia, hypocalcaemia, hereditary fructose intolerance
  • Drugs and alcohol
• Psychiatric disorders
• Psychiatric disorders that may be mistaken for epilepsy: panic disorder, psychosis, attention deficit hyperactivity disorder, depersonalisation disorder
• Dissociative seizures
• Factitious disorder

Investigations

• Investigations will depend on the specific presentation of each patient. Investigations include:
  • A full assessment for the presence of any underlying physical cause for epilepsy, e.g. EEG, MRI brain scan.
  • Investigations for physical causes of non-epileptic seizures, e.g. fasting glucose, electrolytes, ECG, echocardiogram.
  • A full psychiatric assessment.
• Serum prolactin rises in over 90% of patients after a tonic-clonic seizure and 60% of patients after a complex partial seizure. However an increased post-ictal prolactin is non-specific.

Associated diseases

• A significant number of patients (estimated at up to 30%) having mixed epileptic and non-epileptic seizure disorders.

Management

• Management is directed at treatment of the underlying cause.
• Various treatments have been tried with variable success for psychogenic NES. Treatment regimes for NES include non-psychological, e.g. anti-anxiety and antidepressant medication and psychological therapies (including cognitive behavioural therapy, hypnotherapy and paradoxical injunction therapy). With paradoxical injunction therapy, the therapist imposes a directive that places the client in a therapeutic double bind that promotes change regardless of the client's compliance with the directive.
• There is currently no reliable evidence to support the use of any treatment, including hypnosis or paradoxical injunction therapy, in the treatment of NES.⁴

Prognosis²

• A recent review found that, after a mean follow-up of three years, about two thirds of patients continued to have dissociative seizures and more than half remained dependent on social security.
• Receiving psychiatric treatment has been associated with a positive outcome in some studies, but not in others.
• A poor prognosis is predicted by a long delay in diagnosis and the presence of psychiatric comorbidity, including personality disorder.