Harmonization of research methodology, measures, and existing cohort data is needed to advance the field of psychosis epidemiology. The International Psychosis Epidemiology Consortium (IPEC) has been initiated to create a data-sharing platform for psychosis cohorts globally and provide infrastructure for data harmonization. This profile paper describes the design and data harmonization process, and the technical, ethical, and legal steps taken to set up the IPEC virtual databank, as well as the organizational structure we developed for IPEC.
An international group of researchers, collaborating in the Schizophrenia International Research Society—Epidemiology Research Harmonization Group, drafted inclusion and exclusion criteria for participating cohorts and selected, among others, sociodemographic, socioeconomic, and clinical variables for harmonization. Drawing upon current guidelines for data harmonization, a guideline specifically for psychosis cohorts and a software architecture for federated analysis were developed. Finally, as proof of principle, all steps of data harmonization were applied to 2 cohorts, and summary statistics on core variables were calculated.
A platform for remote and nondisclosive analyses of multisite individual-level data and a data catalog with information on IPEC’s variables and harmonization procedures were built. The 6-step design, harmonization procedure, ethical and legal procedures, future organizational structure and how to join IPEC were described. Data harmonization of variables of the 2 proof-of-principle cohorts was successful.
IPEC has created a virtual databank for individual-level data of psychosis cohorts and implemented a technical infrastructure for remote federated analysis. This databank facilitates future large-scale collaborative international psychosis epidemiology research.