For schizophrenia, we obtained the summary statistics from the PGC GWAS of schizophrenia1. This study used 52 independent samples, of them 46 were case control samples of European ancestry, 3 were Asian case control samples and 3 were European family samples. Since the samples were collected from different countries, both the criteria for Diagnostic and Statistical Manual of Mental Disorders (DSM) and International Classification of Diseases (ICD) were used in the diagnosis of the patients. Please see original paper1 for details. We selected to use the summary statistics of the 46 European case control samples (32,405 cases and 46,839 controls). For ND-related traits, we used the summary statistics of our cotinine study65 and 2 unpublished datasets (manuscripts in preparation). One data used the sum scores of the Fagerström Test for Nicotine Dependence (FTND)66 as a trait, which is a commonly used phenotype for ND based on self-reported smoking behaviors. The second data used a single item of the FTND questionnaire, “How soon after you wake up do you smoke your first cigarette”, or time to smoke the first cigarette (TFC)
