First, we and others have shown that when presented with food-related cues, the brain processes information differently when it is on or off leptin. Then, we showed that leptin increases grey matter volume in brain areas, such as the anterior cingulate, which are relevant to addictive behaviour and to depression. We also showed in a leptin-deficient child that leptin replacement therapy drastically increased performance in subscales of neuropsychological testing. Additionally, it has been shown in the elderly that higher levels of endogenous leptin are protective against dementia. Given this exciting background supporting its pro-cognitive actions, human leptin is currently being explored as an experimental treatment for Alzheimer’s disease.