Dissociative Seizures

dissociative seizuresWe have been seeing an increasing number of patients with dissociative seizures at Ormond Neuroscience.  Curious about the epidemiology, I investigated and am startled by the figures!  Approximately 20%-30% of patients who have been diagnosed with refractory epilepsy turn out to have been misdiagnosed and do not have epilepsy at all.  Instead, these patients have dissociative seizures, a complex and debilitating neuropsychological condition.  Worryingly, on average it takes seven years before the correct diagnosis is made.  The cost of the misdiagnosis is enormous for both the patient and society.

Many of these patients are prescribed antiepileptic drugs (AEDs), which they use unnecessarily for several years.  The side-effects of AEDs include moderate impairment of cognitive functioning, daytime sleepiness, gingivitis, and even liver toxicity when the dosage is too high.  Misdiagnosed patients may be unnecessarily hospitalised and are frequently absent from work.  They may be banned from driving, operating heavy machinery, and so on, limitations which restrict their capacity to generate income.  A minority are at risk for iatrogenic complications, such as AED toxicity or even vocal cord injury during intubation while in “status pseudo-epilepticus.”

Études cliniques sur l'hystéro-épilepsie ou grande hystérieDissociative seizures (aka psychogenic seizures, pseudo-seizures, nonepileptic attacks) are believed to be an unconscious and involuntary reaction to psychological stress.  Approximately 10% of patients with dissociative seizures also have genuine refractory epilepsy, which complicates management and diagnosis substantially.  No single sign or symptom of dissociative seizures is pathognomonic, but many differences exist between dissociative seizures and true epileptic seizures.  Video electroencephalography (VEEG) is the gold standard for differential diagnosis, but is not infallible since simple partial seizures and frontal lobe seizures are not invariably accompanied by changes in the ictal scalp EEG.

Giving and Receiving the Diagnosis

Unfortunately, giving and receiving the diagnosis of dissociative seizures is hugely problematic.  The psychodynamics of dissociative seizures are highly complex and patients are likely to resist the idea that their seizures are caused by psychological problems, rather than a neurological abnormality.  Their lives have been structured around the belief that they are suffering from epilepsy, a misperception that has been unwittingly reinforced by years of medical treatment.  Neurologists who have been trying one AED after the next, may be annoyed to find that they have misunderstood the patient’s problem.

These issues all come together at the moment that the diagnosis of dissociative seizures is given to the patient.  It is a make or break event.  If the diagnosis is communicated carefully and skilfully, and the patient accepts the diagnosis, then seizure frequency drops by more than half.  Of great concern, one study found that an alarming 20% of patients with dissociative seizures attempt suicide within 18 months of being given the diagnosis.  Clearly, patients with complex psychological issues may not receive this diagnosis well.  It is relevant that approximately 80% of this patient group have psychiatric comorbidities.

Who should give the Diagnosis?

A strong case can therefore be made that ideally the diagnosis should be communicated by a neuropsychologist who understands the condition and who is able to manage the psychodynamic issues at play, gently leading the patient to a point where they are able to accept and understand the reality of dissociative seizures and not react against the diagnosis.  Inevitably, such a diagnosis needs to be followed up by psychotherapy, often with psychotropic medication as an adjunct.  Please contact us if you need a neuropsychologist to assist with the management and diagnosis of dissociative seizures.


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