Next, we looked at the genetic correlation between the smoking phenotypes and schizophrenia. The genetic correlation, defined here as the proportion of common genetic variation that is shared by two phenotypes, was evaluated between the smoking phenotypes and schizophrenia. Significant genetic correlation was observed between schizophrenia and three of the five smoking phenotypes (p<0.05): ever/never smoker (rg 0.10), CPD (rg 0.12), and nicotine dependence (rg 0.14). The values for ever/never smoker and age of onset are slightly different from those published previously (Bulik-Sullivan et al., 2015a) because the prior study did not use the same schizophrenia GWAS results.
