This study had limitations. Only samples of European ancestry and common genetic variants were included due to limited availability of trans-ancestral and sequenced samples. Both EDU and SWB are influenced by social factors, and neither can be considered direct measures of cognition or personality. Nonetheless, there is a lack of well-powered GWAS of more specific measures within either domain and they provide useful insights alongside intelligence and neuroticism. We also cannot exclude the possibility of co-morbidity or misdiagnosis across psychiatric samples. However, the extent of the overlap observed and its consistency across mental traits indicate that this alone cannot explain our findings. In addition, for all pair-wise analyses of mental disorders and related traits, besides MD and neuroticism, the AIC differences were negative when compared to maximum possible overlap. This indicates that MiXeR modelled estimates of genetic overlap are indistinguishable from maximum overlap as measured by AIC, and so must be interpreted with caution. It is important to note, however, that the overlaps presented are still the best-fitting estimates as determined by maximum likelihood estimation. Finally, given the need to
