Cigarette smoking and psychotic symptoms in bipolar affective disorder

Background An association exists between smoking and schizophrenia, independent of other factors and related to psychotic symptomatology. Aims To determine whether smoking is associated with psychosis in bipolar affective disorder. Method Smoking data were collected from 92 unrelated patients with bipolar affective disorder. An ordinal logistic regression analysis tested the relationship between smoking severity and psychotic symptomatology, allowing for potential confounders. Results A significant relationship was detected between smoking/heavy smoking and history of psychosis (68.7%, n=44). Smoking was less prevalent in patients who were less symptomatic (56.5%, n=13)than in patients with a more severe psychosis (75.7%, n=31). Prevalence and severity of smoking predicted severity of psychotic symptoms (P=0.001), a relationship independent of other variables (P=0.0272). Conclusion A link between smoking and psychosis exists in bipolar affective disorder and may be independent of categorical diagnosis.