Pseudoseizures and asthma

Sexual abuse and head injury are important risk factors of pseudoseizures, reported in about a third of patients. Clinical experience suggests that asthma is another possible risk factor.

To determine the relative prevalence of asthma in patients with pseudoseizures.

A retrospective record review was undertaken of reported asthma in 102 patients with pseudoseizures and 70 psychotic controls. The pseudoseizure patients were subgrouped according to method of diagnosis: 47 in whom epilepsy was excluded by capturing a typical attack on video-electroencephalographic monitoring (VEEM), and 55 not diagnostically confirmed with VEEM.

Asthma was reported in 26.5% of pseudoseizure patients, compared with 8.6% of the psychotic controls (chi(2) = 8.6; p = 0.003). Asthma was reported at similar rates in the VEEM confirmed (29.8%) and non-VEEM confirmed (23.6%) pseudoseizure subgroups. The significant excess of reported asthma held for both the VEEM confirmed subjects (Pearson's chi(2) = 5.4, p = 0.02) and non-VEEM confirmed subjects (Pearson's chi(2) = 8.9, p = 0.003).

There is an association between pseudoseizures and reported asthma. Various models are proposed whereby somatisation, anxiety hyperventilation, and dissociative elaboration may account for the observed association. Both asthma and anxiety hyperventilation may be important risk factors for the development of pseudoseizures. The reported asthma may itself be psychogenic in origin in a proportion of patients. Confirmatory prospective studies are indicated.