Although psychogenic non-epileptic seizures (PNES) are events that appear to be similar to seizures, they are not caused by abnormal electrical brain activity. Instead, they are thought to have an underlying psychological cause.
PNES is classified as a subtype of conversion disorder under the category, somatic symptom and related disorders in DSM-5. When coding for PNES as a conversion disorder using ICD-10, the diagnosis must include the specifier “with attacks or seizures” (ICD-10 code F44.5) to differentiate it from other conversion symptoms (eg, dysarthria, sensory loss), which are coded separately. Alternate names frequently used for PNES are non-epileptic attack disorder, functional seizures, stress seizures, psychogenic seizures, and pseudoseizures. The last has largely fallen out of favor because of the pejorative nature of the term “pseudo,” which may imply that the symptoms are not real and therefore undermine the impact of the disorder on a patient’s life. It is not uncommon to see both PNES and epileptic seizures in the same patient.
PNES has a long history in the medical literature, where it has been described by several aliases, the most common being hysteria. Equally as varied were the many hypotheses for the causes of hysteria. Because of its observed frequency in females, hysteria was conceptualized as the result of a “wandering uterus” that had been displaced in the body and subsequently inhabited other organs and appendages, applying pressure and leading to the manifestation of physical symptoms. This theory eventually lost prominence as symptoms of hysteria were increasingly reported in males.
In the 19th century, the phenomenon became a passion of French neurologist Jean Charcot, who identified it primarily as a neurological disorder with psychological underpinnings that could, in some cases, be treated by hypnosis. Sigmund Freud, after studying under Charcot, theorized the symptoms as a conversion of repressed libidinal impulses into physical form, which brought about its current title of conversion disorder. Alternatively, Pierre Janet suggested hysteria was more of a dissociative phenomenon that occurred at times of stress with the purpose of allowing an individual to re-experience a traumatic event while separating the memory from conscious awareness.
Clues to a possible diagnosis of PNES can be discovered by eliciting a seizure history including onset, typical semiology of the seizure, and treatment. Patients with PNES are likely to have seizures more frequently with more hospital visits than patients with epilepsy. They may often carry a diagnosis of refractory epilepsy, and it is not uncommon for patients to have current or past prescriptions of antiepileptic drugs. Antiepileptic drugs, however, are not effective in treating PNES and may either worsen the symptoms or cause only a transient partial response.
Psychiatric comorbidity is quite common in patients with PNES. The most frequently co-occurring disorders are PTSD, anxiety disorder, personality disorder, and depression (Table 1). Patients with comorbid psychiatric disorders may also have more severe dysfunction and higher levels of stress. Identifying a comorbid psychiatric condition can result in more specific treatments that target those symptoms as well as better outcomes for patients.
In addition to performing a psychiatric review of systems, inquire about any history of medically unexplained symptoms (hand tingling, paralysis, etc) and screen for possible somatoform disorders. Patients with PNES may frequently report pain as other somatic symptoms. Prescriptions for pain medication were found to have a positive predictive value of 76.9% in patients with PNES compared with patients with epilepsy.1
Dr. Abbasi is Consulting Psychiatrist for the Jefferson Comprehensive Epilepsy Center, and Assistant Professor, Psychiatry and Human Behavior, Sidney Kimmel College of Medicine at Thomas Jefferson University Hospitals, Philadelphia, PA. Dr. TsungWai is a Second-Year Resident, Department of Psychiatry and Human Behavior, Thomas Jefferson University Hospitals. The authors report no conflicts of interest concerning the subject matter of this article.
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