A meta-analysis of worldwide studies demonstrates an association between schizophrenia and tobacco smoking behaviors

Schizophrenia patients had a higher prevalence of ever smoking than the general population (9 studies across 6 countries, weighted average OR = 3.1, CI 2.4-3.8) and than severe mentally ill patients (5 studies across 5 countries, OR = 2.0, CI 1.6-2.4). Moreover, in two studies adjusting for confounders schizophrenia patients had an increased risk of starting daily smoking than controls. Thus, people who are going to develop schizophrenia have risk factors that make them more vulnerable to start smoking.