The report by Kendler et al1 on the risk of schizophrenia among relatives of Irish probands is an important genetic study. However, at the end of their report, they included a section on "The Prevalence of Schizophrenia in Ireland," which contains several inaccuracies.
First, they said that "our results do not support previous claims that the prevalence rate of schizophrenia is substantially elevated in the general population either in all of Ireland or in the West of Ireland." The work that they referenced2 claimed that the schizophrenia rate in western Ireland was elevated only for individuals born prior to 1940. The study by Kendler et al1 included only those individuals born in 1930 or later, so there was only a 10-year overlap in the year of birth of the individuals in the two studies. It is surprising that Kendler et al1 did not note this difference because four