Two case histories of patients with a mild intellectual disability and symptoms of psychosis, anxiety and restlesness are presented. Because of psychosis they are treated with antipsychotics. During the course of treatment signs of tardive akathisia (TA) are diagnosed. The diagnosis of TA proved to be essential in the further treatment course. TA is a common phenomenon but is often overlooked. The diagnosis, differential diagnosis, prevalence, pathophysiology and treatment of TA are discussed. Particularly in patients with a mental handicap as well as in patients with chronic schizophrenia the diagnosis is often difficult because restlesness and anxiety may be experienced in a different manner and because adequate expression of these feelings is difficult for these patients.