Smoking habits in bipolar and schizophrenic outpatients in southern Israel

Background: Although rates of cigarette smoking have been found to be highe r in schizophrenic and depressed patients than in the general population, d ata regarding rates in bipolar patients are limited. This study further exa mines the relationship between bipolar disorder and smoking and compares th e rate of smoking in bipolar disorder patients with rates in schizophrenic patients and in the general population. Method: Seventy bipolar patients and 64 schizophrenic patients (diagnosed u sing DSM-IV criteria) treated at the largest specialized public bipolar and schizophrenia clinics in southern Israel were interviewed regarding their smoking habits. The interview included a questionnaire relating to personal information, past and present smoking, and drug abuse and the Fagerstrom s cale for nicotine dependence. Data from these patients were also compared w ith data from the general Israeli population. Results: Data indicate that the rate of smoking does not appear to differ b etween bipolar (43.0%) and schizophrenic (45.0%) patients, whereas the rate for both patient groups is higher than that for the general Israeli popula tion (27.5%). Smoking intensity was not found to be different between the 2 groups of patients. Conclusion: Smoking in patients with schizophrenia was suggested to be rela ted to nicotine cholinergic dysfunction, but this suggestion cannot explain the equally high rates of smoking in bipolar patients. Schizophrenia, bipo lar disorder, and smoking may all be related to dopamine transmission, and, therefore, dopaminergic interactions may provide a better explanation for the results.