BACKGROUND: This study tests the hypothesis that epilepsy increases the risk of developing schizophrenia and other non-affective functional psychoses using a nationwide sample of people with epilepsy. METHOD: A record linkage study between a sample from the National Patient Register, consisting of 67,116 people with epilepsy, and the Danish Psychiatric Register identified all people with non-affective psychoses with onset after the first epilepsy diagnosis. The relation between risk of psychiatric disorder in people with epilepsy and the general Danish population was estimated. RESULTS: The incidences of the spectrum of non-organic non-affective psychosis, non-affective psychosis and schizophrenia were significantly increased both for men and women, even after exclusion of people diagnosed as suffering from a learning disability or substance misuse. CONCLUSION: This study supports the notion of an association between epilepsy and the risk of subsequent non-affective psychosis.