There may be a good reason why some people are not able to stop smoking cigarettes．A new study found that people who suffer from depression were two times as likely to fail when they tried to stop smoking.
Alexander Glassman presented the findings recently during the yearly meeting of the American Psychiatric Association．Doctor Glassman is the director of an antismoking center at Columbia University in New York City．His study examined 100 smokers who have a history of depression．People with depression suffer periods of extreme sadness.
The researchers studied people who have succeeded and those who have failed in their efforts to stop smoking．The study found that people who did stop smoking were two times as likely to suffer from depression again within six months as those who continued to smoke.
Doctor Glassman says smokers who are depressed use tobacco to make themselves feel better．But, he says people with depression seem to have a much harder time stopping than non-depressed smokers.
So, drugs to fight depression are now also being used to help people stop smoking．Doctors say the most effective one is called Buproprion.
Buproprion mainly affects the brain chemical dopamine(多巴胺)．nicotine(尼古丁) is a substance in tobacco that also affects dopamine．Buproprion helps people stop smoking because it eases the body's desire for nicotine．Doctor Glassman says the drug does not make people stop smoking．But it makes it easier for those who want to stop.
When people with depression tried to stop smoking they are ______.