Risperidone is a novel antipsychotic that shows a high affinity with 5HT2A, 5HT7, α1, H1, D2, α2, and 5HT2D receptors, and although it belongs to atypical agents, it has been found to exceed in hyperprolactinaemia compared to conventional antipsychotic drugs [45]. This evidence concerns the gene HTR2A and hyperprolactinemia.