1. appeared to exhibit a poorer response to clozapine compared to non-carrier subjects. Nonetheless, a meta-analysis by Hwang et al. pointed to a lack of association between the DRD3 Ser allele and response to clozapine;J�nsson;Several studies have explored the role of polymorphisms in the DRD1, DRD2, DRD4, and DAT genes,1996
2. found significant regional brain metabolic changes associated with DRD1 gene variants, that parallel substantial clinical improvements during clozapine treatment. However, evidence supporting the role of genetic variations of the D1R is conflicting;; Malhotra;Potkin,2003
3. Another gene-gene interaction analysis showed that patients with the COMT Val/Met or Met/Met genotype, with a concomitant DRD4 polymorphism, had a significantly better clinical response to clozapine compared to non-carriers;Bosia;HT 1A R genes on the clinical response, showing that clozapine-treated patients carrying COMT Val/Val and 5-HT 1A R G/G genotypes achieved greater improvement in the negative symptom domain,1995