Genetic removal of CB1 receptors alters social interactions in mice in a context-dependent manner,32 which may be related to social anxiety and/or cognition.37,38 CB1 agonists impair social play in rats.39 In contrast, genetic removal of FAAH in mice increases social interactions,13 and FAAH inhibition promotes social play in rats.14 Thus, the bidirectional modulation of social behavior likely depends on the dose and the identity of the affected circuits. This evidence concerns the gene FAAH and Anxiety.