We found that five of the 20 SNPs are in loci in which genome-wide significant associations have previously been reported. Two of these five are schizophrenia loci. Interestingly, one of them harbors the gene DRD2, which encodes the D2 subtype of the dopamine receptor, a target for antipsychotic drugs29 that is also known to play a key role in neural reward pathways30. Motivated by these findings, as well as by the modest genetic correlations with schizophrenia reported in Figure 2b, we examined whether the SNPs identified in a recent study of schizophrenia31 are enriched for association with neuroticism in our non-overlapping UKB sample (N = 107,245). We conducted several tests and found strong evidence of such enrichment (Supplementary Note). For example, we found that the p-values of the schizophrenia SNPs tend to be much lower than the p-values of a randomly selected set of SNPs matched on allele frequency (p = 6.50×10−71).
