title: Sexual dysfunction in male schizophrenia: influence of antipsychotic drugs, prolactin and polymorphisms of the dopamine D2 receptor genes.
abstract: OBJECTIVE
  Sexual dysfunction induced by antipsychotic drug treatment is under investigated and under reported. This study aimed to determine the influence of genetic polymorphisms in the D2 dopamine receptor (DRD2) and endothelial nitric oxide synthase (eNOS) genes, and the possible role of blood prolactin concentrations on sexual function in schizophrenic patients.
  
  
  METHODS
  Male remitted schizophrenic patients (n = 100), who were living with a sexual partner and receiving antipsychotic drug monotherapy for at least 6 months, were assessed for sexual and erectile dysfunction using the Arizona Sexual Experience Scale and the five-item version of the International Index of Erectile Function. Blood samples were taken for plasma prolactin determination and genotyped for four polymorphisms: DRD2 (-141C Ins/Del and Taq1A) and eNOS gene (G894T and T-786C).
  
  
  RESULTS
  The -141C Ins/Del, but not Taq1A, polymorphism of the DRD2 gene was significantly associated with sexual dysfunction with the del allele being less frequent in sexual dysfunction subjects. Neither of the eNOS polymorphisms, G894T or T-786C, was significantly associated with sexual or erectile dysfunction. Prolactin concentrations were significantly higher in patients with erectile dysfunction but did not reach significance in those with sexual dysfunction. Prolactin was also reduced in -141C Del allele carriers. The frequency and severity of sexual dysfunction in the patients receiving typical antipsychotics was significantly greater than those receiving risperidone or clozapine, while prolactin concentrations were significantly higher in subjects receiving risperidone compared with those receiving clozapine or typical antipsychotics.
  
  
  CONCLUSIONS
  This is the first evidence indicating that antipsychotic drug treatment in men is associated with a variant in the DRD2 gene in which the -141C Del allele might be a protective factor. While this may, in part, be mediated by effects on prolactin, other factors are likely to contribute to the greater sexual dysfunction in patients receiving typical antipsychotics.
authors.affiliation: Neuropsychiatric Research Institute, School of Medicine, Southeast University, Nanjing, China.
authors.forename: Xiang Rong
authors.initials: XR
authors.lastname: Zhang
authors.forename: Zhi Jun
authors.initials: ZJ
authors.lastname: Zhang
authors.forename: Rong Xin
authors.initials: RX
authors.lastname: Zhu
authors.forename: Yong Gui
authors.initials: YG
authors.lastname: Yuan
authors.forename: Trisha A
authors.initials: TA
authors.lastname: Jenkins
authors.forename: Gavin P
authors.initials: GP
authors.lastname: Reynolds
mesh_terms: D000328:Adult; D014150:Antipsychotic Agents / Q000009:adverse effects* / Q000627:therapeutic use; D044466:Asian People; D002681:China / Q000453:epidemiology; D004247:DNA / Q000235:genetics; D039721:Diagnostic and Statistical Manual of Mental Disorders; D007172:Erectile Dysfunction / Q000139:chemically induced / Q000235:genetics; D005838:Genotype; D006801:Humans; D008297:Male; D008875:Middle Aged; D052250:Nitric Oxide Synthase Type III / Q000235:genetics; D011110:Polymorphism, Genetic / Q000235:genetics; D020641:Polymorphism, Single Nucleotide / Q000235:genetics; D011388:Prolactin / Q000097:blood / Q000502:physiology*; D011569:Psychiatric Status Rating Scales; D017448:Receptors, Dopamine D2 / Q000235:genetics*; D012559:Schizophrenia / Q000150:complications* / Q000188:drug therapy*; D012735:Sexual Dysfunction, Physiological / Q000139:chemically induced* / Q000235:genetics*
chemical_list: D014150:Antipsychotic Agents; D017448:Receptors, Dopamine D2; D011388:Prolactin; D004247:DNA; D052250:Nitric Oxide Synthase Type III