Moreover, although previous clinical studies have shown how this SERT blocker decreases appetite (Silverstone, 1992; Michelson et al., 1999), a recent metanalysis study (Serralde-Zúñiga et al., 2019) comparing different categories of anti-obesity drugs indicates that, unlike other drugs, fluoxetine treatment does not conclusively decrease weight, but there is a clear increase in the risk for drowsiness and fatigue. Here, SLC6A4 is linked to obesity due to melanocortin 4 receptor deficiency.