The diagnosis of pseudo-epileptic seizures (PES) is confirmed in 7-10% of the patients that are considered to suffer from 'refractory epilepsies'. As yet no consistent model is available to explain the development of PES in individual patients. This open non-randomized clinical study aimed at assessing behavioural mechanisms that trigger PES, independent of the underlying personality characteristics. Twenty-four patients with PES were compared with pairwise matched patients that suffered exclusively from genuine epileptic seizures (ES). The patients were assessed with two personality inventories that measured potential important behavioural mechanisms: the 19 PF-form B of the Cattell IPAT Anxiety Scale and the Dutch ABV-scale, largely based on Eysenck's Maudsley Personality Inventory. This assessment was complemented with individual history taking and psychiatric examination. The results are presented in a model in which three factors are involved that have a combined effect on the development of PES in individual patients: personality disorders (of heterogeneous origin), the behavioural mechanism of somatization and a familiarity with epilepsy as a modifying factor.