Fatty Acid Amide Hydrolase (FAAH) is an enzyme involved in the metabolism of endocannabinoids, located in the cellular membranes, particularly in the central nervous system and peripheral tissues. It regulates pain, mood, and hunger by hydrolyzing endogenous cannabinoids such as anandamide and 2-arachidonoylglycerol. There are individual differences in FAAH gene expression, which affect the regulation of the endocannabinoid system. Specific genetic variations are associated with pain sensitivity, anxiety, and other psychological states, making FAAH inhibitors potential targets for treating related disorders.