The authors would like to express their gratitude to the families participating in the study; to H. B. Stadsgaard, Å. K. Prøsch, M. Melau, A. M. Bundsgaard, A. F. Bundgaard, M. Birk, N. L. Steffensen, L. J. Mikkelsen, and L. Carmichael for contributing to the data collection; to C. B. Pedersen and M. G. Pedersen for retrieving the register extract; and to M. K. Rimvall for valuable knowledge regarding psychotic experiences.