Amygdala reactivity to threatening stimuli appears to be abnormal in schizophrenia [68]. Only three studies have examined the genetic liability of faces/emotion processing in subjects at increased genetic risk for schizophrenia [18, 69, 70], with inconsistent results (Supplementary Table 1.E). Indeed, the largest study [18 ·] found no evidence of an abnormality in healthy sibs. This circuit has been extensively explored in imaging genetics, and results seem to suggest that it is vulnerable to modulation by genes increasing the risk for affective disorders [10, 71], while genes associated with risk for schizophrenia seem to be protective (e.g val/val subjects in the COMT functional val/met genotype have reduced amygdala reactivity to threatening stimuli [7, 72] (Supplementary Table 2.E). In conclusion, genes impacting this circuit, if associated with risk for schizophrenia, likely increase the risk for the disorder through a mechanism different from their effect on amygdala reactivity.
