Second, the higher prediction accuracy of the PRS obtained using the full sample of GPpsy could be entirely explained by the larger sample size52 (113,260 cases and 219,362 controls; effective sample size = 298,677; Supplementary Note and Extended Data Fig. 7). We calculated the effective sample size needed for other definitions to have the same predictive power: for strictly defined LifetimeMDD, we would need an effective sample size of 129,106 (Supplementary Note and Extended Data Fig. 7), less than half of that of GPpsy.
