FAAH and major depressive disorder: Multiple studies have shown that chronic i.p. injection of the FAAH-inhibitor URB597 (0.2, 0.3, 0.4, 5.8 mg/kg), which increases AEA levels, prevents depressive-like behaviors induced by different models and methods, such as CUMS [98], adolescent THC exposure [99], CMS [100] and chronic constriction injury (CCI) that induces neuropathic pain and depression-associated behavior [101].