Psychiatric genomics has made amazing advances over the last decade, revealing high levels of polygenicity and pleiotropy across disorders, shared functional pathways, and patterns of genetic overlap modeled to identify clusters of disorders. Even still, we have only just begun to understand the cumulative genetic architecture across psychiatric traits. An obvious next step is to continue to collect more data. To this end, the PGC has set the goal of obtaining GWAS data on 100,000 cases for each major disorder (Sullivan et al., 2018). These efforts will also include whole genome and exome sequencing efforts that aim to capture more rare variants. Larger sample sizes coupled with sequencing efforts will certainly uncover more associated variants and, given sizeable SNP-based co-heritability estimates, many of these variants are likely to be pleiotropic. At the same time, it is estimated that even with samples of 500,000 cases and controls (i.e., total N = 1,000,000), identified risk variants will account for 60% of the SNP-based heritability for SCZ and BIP, and only 10% of the SNP-based heritability for MDD (Holland et al., 2019). Identifying
