Consistent with a purported role for mGlu5 in regulating anxiety (reviewed in Bergink et al., 2004; Swanson et al., 2005; Simon and Gorman, 2006), systemic treatment with negative allosteric modulators of mGlu5 alleviates signs of withdrawal-induced anxiety in rodents (Kotlinska and Bochenski, 2008; Kumar et al., 2013; Lee et al., 2017a,b). Here, GRM5 is linked to Anxiety.