The RF classifier identified BIS impulsivity scores as among the top significant variables to classify AUD from the CTL individuals. The AUD group showed significantly increased impulsivity compared to the controls. This finding supports the existing view that impulsivity is a core feature of substance use disorders and may result from impaired inhibitory control [154]. We have also observed that seven of the FC variables showed significant correlations with one or more BIS scores (Figure 7). Interestingly, three of the beta band connections of R.PCC with bilateral PFC and L.PHG, which showed hyperconnectivity in AUD, were also significantly associated with three of the BIS scores (except non-planning). Since beta oscillations are associated with AUD [155] and other externalizing traits [156], associations among beta band FC, impulsivity and hyperconnectivity in AUD are in line with the view that AUD is primarily a disinhibitory disorder [111] and may be related to neuronal hyperexcitability [108]. Interestingly, similar to the current findings, impulsivity factors ranked as the topmost predictors in our previous study on fMRI FC with the same set of participants [54]. Earlier
