Finally, we computed polygenic risk scores and tested for association between the score and each endophenotype. A polygenic risk score is a weighted sum of risk alleles across many variants, with the weight of each variant equal to the effect size for that variant in the PGC schizophrenia results. More formally, for individual i, their polygenic risk score for variants j through n is: PRSi=∑j=1nln(PGC odds ratioij)×(number of risk allelesij).
