Chunk #10 — Three examples of misspecified models in the G×E literature — Kaufman et al., 2004: A gene-by-environment or an ethnicity-by-environment interaction?
maltreated African Americans are less likely to report depression than maltreated non-African Americans, some or all of the detected G×E interaction may have been due to ethnicity moderating the effect of maltreatment. Somewhat less plausibly, it is also possible that the effect of 5HTTLPR on depression depends on ethnicity. If African Americans in the sample had different rates of maltreatment, a 5HTTLPR-by-ethnicity interaction might also have caused the apparent 5HTTLPR-by-maltreatment interaction. Because the authors failed to include the environment-by-ethnicity and gene-by-ethnicity interaction terms, these alternative explanations for their findings cannot be ruled out.
