Tobacco smoking and schizophrenia: re-examining the evidence

SUMMARYTobacco smoking among people with mental illnesses can be explained by biological, psychological and social factors. The prevalence of smoking in people diagnosed with schizophrenia is higher than in people with other mental disorders and in the general population. This article explores three current hypotheses that explain this higher prevalence of smoking in schizophrenia. The first, the self-medication hypothesis, is increasingly countered by a growing body of evidence indicating that smokers experience more severe symptoms of schizophrenia. Numerous researchers have already identified smoking as a possible risk factor for the development of schizophrenia, which is the second hypothesis. The third hypothesis (shared genetic vulnerability) identifies certain genes that confer vulnerability for both schizophrenia and nicotine dependence. Understanding the reasons behind the higher prevalence of smoking among people with schizophrenia is vital in planning effective primary, secondary and tertiary smoking prevention for these individuals.LEARNING OBJECTIVESAt the end of this article, readers will be able to: •understand the self-medication hypothesis in relation to tobacco smoking by people with schizophrenia•understand the role of tobacco smoking as a possible risk factor for causation of schizophrenia•understand the role of shared genetic vulnerability in the causation of both schizophrenia and nicotine dependence.