There are limitations to this study. Polysubstance use is prevalent amongst those with family histories of alcoholism (Nurnberger et al., 2004). Although we strove to exclude other substance abuse, some subjects who denied drug use ultimately tested positive for illicit drugs. However, eliminating the HD-FHP subject who tested positive for stimulants on the day of the placebo session did not change the significance of the Group × Odor × Condition interactions. Even after eliminating all four HD subjects who tested positive at any session, voxel-wise testing continued to show the same trends (HD-FHP with a larger right mPFC [AO > ApCO] response under placebo than HD-FHN at [6, 66, 0] at p < 0.001, uncorrected; HD-FHN with greater responses than HD-FHP in the left vmPFC [−12, 42, −8], p = 0.001). Thus, the limited illicit drug use in this sample did not principally drive the effects. Power constraints also preclude assessing interactions with gender or nicotine use.
