title: Smoking and tardive dyskinesia: lack of involvement of the CYP1A2 gene.
abstract: OBJECTIVE
  To establish if there is an association between cigarette smoking and tardive dyskinesia (TD) in patients with schizophrenia and to evaluate the role of the CYP1A2 polymorphism in TD in patients of Chinese descent.
  
  
  METHODS
  Two-hundred and ninety-one patients diagnosed with schizophrenia according to DSM-IV criteria were included in the study. Dyskinesia was assessed by the Abnormal Involuntary Movement Scale and TD by the criteria of Schooler and Kane. Demographic and clinical data and information on smoking habits were collected, and patients of Chinese descent with a well established smoking history were subsequently genotyped for CYP1A2.
  
  
  RESULTS
  Forty-three (41.3%) of the 104 patients with a history of smoking and 52 (27.8%) of the 187 non-smokers were diagnosed with TD. The prevalence of TD was significantly higher among smokers than non-smokers (chi2 = 5.57, p = 0.018). Logistic regression using TD as the dependent variable revealed smokers to be at a significantly higher risk for TD (p < 0.005). Genotyping of smokers of Chinese descent for CYP1A2 polymorphism revealed no significant differences in the genotypic or allelic distribution between those with and without TD.
  
  
  CONCLUSIONS
  Consistent with other studies, the prevalence of TD was significantly higher among smokers than non-smokers; however, we did not find an association between the C --> A genetic polymorphism of CYP1A2 and TD.
authors.affiliation: Woodbridge Hospital and Institute of Mental Health, Singapore. CHONG_Siow_Ann@imh.com.sg
authors.forename: Siow-Ann
authors.initials: SA
authors.lastname: Chong
authors.forename: Ene-Choo
authors.initials: EC
authors.lastname: Tan
authors.forename: Chay Hoon
authors.initials: CH
authors.lastname: Tan
authors.lastname: Mythily
mesh_terms: D019388:Cytochrome P-450 CYP1A2 / Q000235:genetics*; D004409:Dyskinesia, Drug-Induced / Q000175:diagnosis / Q000453:epidemiology / Q000235:genetics*; D005260:Female; D015870:Gene Expression / Q000235:genetics*; D005838:Genotype; D006801:Humans; D008297:Male; D008875:Middle Aged; D011110:Polymorphism, Genetic / Q000235:genetics; D015995:Prevalence; D012559:Schizophrenia / Q000150:complications; D012720:Severity of Illness Index; D012907:Smoking / Q000453:epidemiology; D014026:Nicotiana / Q000009:adverse effects*; D014029:Tobacco Use Disorder / Q000150:complications / Q000453:epidemiology
chemical_list: D019388:Cytochrome P-450 CYP1A2