Psychogenic non-epileptic seizures: aetiology, diagnosis and management

Psychogenic non-epileptic seizures (PNES) can be defined as paroxysmal events that resemble or can be mistaken for epilepsy, without being associated with abnormal electroencephalogram (EEG) activity or any other primary physiological disturbance. Most are interpreted as a behavioural or experiential response to overwhelming distress (Reuber 2008). Psychogenic non-epileptic seizures sit uneasily within the current psychiatric classification systems, classified as a dissociative (conversion) disorder (‘dissociative convulsions’) in ICD-10 (World Health Organization 1992) and as a somatic symptom disorder in DSM-5 (American Psychiatric Association 2013). However, many patients also fulfil the criteria for mood and anxiety disorders, post-traumatic stress disorder, episodic dyscontrol and, in a minority, factitious disorder (Bodde 2009). Some PNES-like events are probably malingered but the overwhelming majority of patients are thought to have seizures which are not wilfully produced. At least 15 different terms have been used to describe this clinical phenomenon, including: pseudo seizures, dissociative seizures, functional seizures, hysterical seizures and non-epileptic attack dis order. Some of these terms (especially hysterical seizures and pseudoseizures) are unacceptable to patients (or question the veracity of their experience) and have been abandoned or should be discouraged (Stone 2003). For the purpose of this article, we will use the term PNES, which has been used most commonly in recent research. Here we offer an overview of the main aspects of PNES. Although informed as comprehensively as possible by published evidence, it must be made clear that the article reflects our own views and clinical experience.