More interestingly, previous studies have also found that long-term use of clozapine, which has a strong blockade of the D1 dopamine receptor, a weak blockade of the D2 dopamine receptor, and an anticholinergic effect, improves verbal fluency in patients with schizophrenia [47], while, risperidone, the antagonist of the D2 dopamine receptor, presents similar improvement in verbal fluency in patients with schizophrenia compared with clozapine [47]. The gene discussed is DRD1; the disease is schizophrenia.