The paradoxical reduction of dopamine function associated with obesity despite reduced sensitivity to leptin/insulin is likely a (pathological) adaptation as well, as frequently proposed in theories likening obesity to addiction (Volkow and Wise, 2005; Trinko et al., 2007; Avena et al., 2009; Lutter and Nestler, 2009; Avena and Bocarsly, 2011). The gene discussed is LEP; the disease is obesity due to melanocortin 4 receptor deficiency.