FAAH and obesity due to melanocortin 4 receptor deficiency: For example, our results are similar in magnitude to those of Spagnolo et al. who find a robust effect of the FAAH genotype (~15–20%) in a small sample of participants with co-morbid posttraumatic stress disorder and alcohol use disorder [74]; with those of Mayo et al. who report 19% (p = 0.04) higher AEA in AC + AA [75] and with those of Sipe et al. who find 11% (p = 0.04) higher FAAH substrates in HC participants (n = 144; including participants with obesity) [66].