Risperidone also has a strong binding affinity to 5-HT2A while quetiapine has a weak binding affinity to 5-HT2A, abruptly switching from risperidone to quetiapine may cause a serotonin syndrome or neuroleptic malignant syndrome (NMS) symptom [44]. The gene discussed is HTR2A; the disease is neuroleptic malignant syndrome.