Chunk #88 — 7.0 Recommendations to Advance Endophenotype Genetics — 7.3 Adequate power to detect individual effects is crucial but almost never attained in existing endophenotype genetic association studies — 7.3.1. Power and sampling schemes in GWAS
is difficult, to say the least. Indeed, any other variable, including an endophenotype, that correlates with depression in this sample will be subject to the same difficulty, rendering this depression-based sampling scheme limited for understanding anything other than depression. A common approach is to conduct genetic associations studies for a new phenotype Y within each sampling cell (e.g., analyze separately those screened for high depression and the controls), and then meta-analyze the results, but then all the original advantages of selecting based on depression are lost.
