processing/executive functioning. The common COMT functional variant, Val158Met, bidirectionally regulates the enzymatic activity of the encoded enzyme which impacts the efficiency of prefrontal-mediated cognition, specifically executive functioning, working memory, fluid intelligence and attentional control. (Dickinson and Elvevag, 2009). The same common functional COMT polymorphism was associated with abstinence-related working memory deficits in two independent samples of smokers (Ashare et al., 2013) and differentially modulates stress and anxiety responses as well as brain endogenous opioid function (Goldman et al., 2005b).
