By Josepha Chong, MD

Depression is associated with an increased frequency of smoking. Addicted smokers are characterized by preoccupation with smoking, abnormal attachment to cigarettes and anticipation of brain reward from the drugs in cigarette smoke. Attempts to quit smoking often lead to a decreased level of pleasure and undesirable mood swings. Thus, once the brain has adapted to the daily dose of the drug, it seems abnormal to the brain if the user attempts to abstain.

Individuals with underlying or current depressive symptoms are more likely to experience mood disturbances when they attempt to quit. Furthermore, it appears that smoking may mask an underlying depression in some smokers.

New research has suggested that there may be something in cigarette smoke that has antidepressant properties, which explains why cigarette smoking is much more common among depressed patients. A survey of 3,000 individuals in the St. Louis area confirmed that lifetime frequency of major depression was more common among smokers than nonsmokers (6.6 vs. 2.9 percent). This study also demonstrated that smokers who reported at least one episode of major depression were less likely to succeed in smoking cessation programs than smokers without depression (14 vs. 28 percent). These findings have been confirmed many times over.

There are thousands of chemicals other than nicotine constituents in cigarette smoke, of which one, or several, may affect mood in much the same way as a group of antidepressant medications called monoamine oxidase inhibitors or (MAOIs). These MAOIs effectively increase levels of specific neurotransmitters involved in the regulation of mood. Smoking, therefore, may be a way for depressed individuals to self-medicate depressive symptoms . Consequently, healthcare professionals who offer smoking cessation programs should offer depression screening and be prepared to address underlying mood disorders as part of a comprehensive smoking cessation program.