New data and an old puzzle: the negative association between schizophrenia and rheumatoid arthritis. - Lee SH; Byrne EM; Hultman CM; Kähler A; Vinkhuyzen AA; Ripke S; Andreassen OA; Frisell T; Gusev A; Hu X; Karlsson R; Mantzioris VX; et al. (International journal of epidemiology, 2015)