The aetiology is complex. It is thought that psychogenic factors (anxiety, dissociation, non-dissociative post-traumatic stress, sexual abuse, personality disorder, interpersonal difficulties, social and family problems) as well as somatic factors, such as chronic disease or intellectual disability may play a role.
The pattern taken by the seizures varies. PNES may resemble all types of epileptic seizures, from brief episodes of absence to major convulsive seizures. However, these seizures frequently last longer than epileptic seizures, which are usually over after 1 – 2 minutes. The condition is categorised under conversion disorders or dissociative disorders, possibly as «other unspecified seizures» within the ICD and DSM classification systems.
The condition may be regarded as «a behavioral response to mental, physical or social stress characterized by a temporary loss of control» (2). Many of those affected have lived for many years with a diagnosis of epilepsy and have taken anti-epileptic drugs. It is estimated that around 20 % of patients referred to epilepsy centres for refractory epilepsy have PNES (3). It comes as a surprise to many that the seizures prove not to be a component of epilepsy.
The patient group is very heterogeneous. The condition is most frequently seen in young girls, but occurs in both sexes and at all ages. Many drop out of school and working life. Psychiatric comorbidity is common, and it is estimated that only 5 % of those with PNES do not have a comorbid psychiatric condition (1).