Genome-wide analyses of empathy and systemizing: heritability and correlates with sex, education, and psychiatric risk

Empathy is the drive to identify the mental states of others and respond to these with an appropriate emotion. Systemizing is the drive to analyse or build lawful systems. Difficulties in empathy have been identified in different psychiatric conditions including autism and schizophrenia. In this study, we conducted genome-wide association studies of empathy and systemizing using the Empathy Quotient (EQ) (n = 46,861) and the Systemizing Quotient-Revised (SQ-R) (n = 51,564) in participants from 23andMe, Inc. We confirmed significant sex-differences in performance on both tasks, with a male advantage on the SQ-R and female advantage on the EQ. We found highly significant heritability explained by single nucleotide polymorphisms (SNPs) for both the traits (EQ: 0.11 ± 0.014; P= 1.7x10-14 and SQ-R: 0.12 ± 0.012; P=1.2x10-20) and these were similar for males and females. However, genes with higher expression in the male brain appear to contribute to the male advantage for the SQ-R. Finally, we identified significant genetic correlations between high score for empathy and risk for schizophrenia (P= 2.5x10-5), and correlations between high score for systemizing and higher educational attainment (P= 5x10-4). These results shed light on the genetic contribution to individual differences in empathy and systemizing, two major cognitive functions of the human brain.