The design of the prenatal determinants of schizophrenia study

This paper describes the Prenatal Determinants of Schizophrenia (PDS) Study ; three companion papers report the first results. The PDS Study was design ed to study early antecedents of schizophrenia in a birth cohort of 1959-19 67 for whom a wealth of archived prenatal data-including maternal sera-was available, Making use of the registries of a health plan into which the coh ort was born, we ascertained and then diagnosed 71 cases of schizophrenia a nd spectrum disorders in the cohort. We describe herein the available prena tal data, the process of case diagnosis, and the strategies used to analyze prenatal determinants of schizophrenia in this cohort. Data are presented that bear on the main sources of potential bias and are important to unders tanding the strengths and limitations of this unique data set.