Characteristics of 698 patients with dissociative seizures: A UK multicenter study

Objective: We aimed to characterise the demographics of adults with dissociative (non-epileptic) seizures, placing emphasis on distribution of age at onset, male:female ratio, levels of deprivation and dissociative seizure semiology. Methods: We collected demographic and clinical data from 698 adults with dissociative seizures recruited to the screening phase of the CODES Trial, from 27 neurology/specialist epilepsy clinics in the United Kingdom. We described the cohort in terms of age, age at onset of dissociative seizures, duration of seizure disorder, level of socio-economic deprivation and other social and clinical demographic characteristics and their associations. Results: In what is, to date, the largest study of adults with dissociative seizures, the overall modal age at dissociative seizure onset was 19; median age at onset was 28 years. While 74% of the sample was female, importantly, the male:female ratio varied with age at onset, with 77% of female but only 59% of male participants developing dissociative seizures by age 40. The frequency of self-reported previous epilepsy was 27%; nearly half of these epilepsy diagnoses were retrospectively considered erroneous by clinicians. Patients with predominantly hyperkinetic dissociative seizures had a shorter disorder duration prior to diagnosis in this study than patients with hypokinetic seizures (p<0.001); dissociative seizure type was not associated with gender. Predominantly hyperkinetic seizures were most commonly seen in patients with symptom onset in their late teens. Thirty percent of the sample reported taking anti-epileptic drugs; this was more common in men. Over 50% of the sample lived in areas characterised by the highest levels of deprivation and over two-thirds were unemployed. Significance: Females with dissociative seizures were more common at all ages while the proportion of males increased with age at onset. This disorder was associated with socio-economic deprivation. Those with hypokinetic dissociative seizures may be at risk for delayed diagnosis and treatment.