This project tests two hypotheses concerning the low smoking cessation rates in smokers with schizophrenia. The first hypothesis is that smokers with schizophrenia experience stronger and more sustained effects of smoking abstinence on negative mood and smoking urge than control smokers without psychiatric illness. The second hypothesis is that smokers with schizophrenia experience stronger reinforcing effects of a smoking lapse (i.e., more rewarding effects of smoking after a period of abstinence) than control smokers without psychiatric illness.