The patient samples in the NIMH (N=54) and the CATIE study (N=364) are too small to predict with any statistical certainty whether or not individuals with the KCNH2 3.1 isoform were more likely to experience QT/QTc prolongation and related events, since torsade de pointes is extremely rare (3). In phase 1 of the CATIE study (4), 0/231 QTc prolongation events were reported in the olanzapine group, 6/214 (3%) in the quetiapine group, 7/218 (3%) in the risperidone group, 2/172 (1%) in the perphenazine group, and 2/148 (1%) in the ziprasidone group; these values were not statistically different, and there were no instances of torsade de pointes. Citrome and Stroup (5) calculated the number needed to harm based on these data and found it was between 31.1 and 86. Were these patients with QTc prolongation treatment responders? Did they carry the isoform KCNH2 3.1?