CNR1 and Anxiety: Studies on CB1 conditional knockout (KO) mice, such as the Glu-CB1-KO and GABA-CB1-KO lines, where CB1 is absent in cortical glutamatergic and in forebrain GABAergic neurons, respectively, revealed crucial involvement of the eCB system in anxiety behavior and stress processing (Rey et al. 2012; Bath et al. 2017; Dubreucq et al. 2012).