Smoking and tardive dyskinesia in male patients with chronic schizophrenia

Interactions between smoking and movement disorders include the contrasting associations of more cigarette smoking with reductions in Parkinson's disease and increases in tardive dyskinesia (TD) symptoms. Here we examine the relationship between smoking and TD in a large sample of inpatients with schizophrenia. We used cross-sectional naturalistic methods to analyze the prevalence and severity of neuroleptic-induced TD in relation to cigarette smoking among 764 male chronic and medicated inpatients meeting DSM-IV criteria for schizophrenia. We administered a detailed questionnaire including general information, medical and psychological conditions, and smoking behaviors. We evaluated TD severity using the abnormal involuntary movement scale (AIMS) and psychopathology using the Positive and Negative Syndrome Scale (PANSS). The main statistical analyses used cross-tabulations for the prevalence of TD by smoking and multivariate regression analyses for continuous measures (AIMS and PANSS). We found that the prevalence of TD did not significantly differ between smokers (41%=237/578) and non-smokers (37%=69/186). Secondary outcomes showed a significant association between the AIMS total score and age, duration of illness and hospitalization times. Thus, smoking was not associated with TD in male Chinese schizophrenics, but consistent with previous reports, older patients with a longer duration of illness and more hospitalizations showed greater severity of TD.