FAAH and major depressive disorder: Preclinical studies suggest that augmenting AEA and 2-AG levels can reduce anxiety- and depression-like behaviors following acute and chronic stress [28–32], while translational research with humans, for instance via genetic polymorphisms in the human FAAH gene or administration of FAAH inhibitors, shows that increased AEA levels can confer anxiolytic and stress-resilient effects [33, 34].