Syncope was associated linearly with CYP2D6 saturation/inhibition (p = 0.050, and OR 1.42 [1.02–1.98]), while headache was again reversely associated with CYP2D6 saturation/inhibition (p < 0.001, and OR 0.38 [0.26–0.55]). The gene discussed is CYP2D6; the disease is Headache.