Psychiatric/behavioural problems can have a major effect on quality of life. Epidemiological studies in Europe, Scandinavia and the USA have confirmed a high rate of psychiatric disorder in children with epilepsy, typically around 35 to 50%. In children with additional impairment, particularly those with intellectual disability, the rates are even higher, over 50%. Determining the causes of these high rates and deciding on the best strategies, either for prevention or for optimal management, remain major challenges.