Epidemiologic evidence supports that there is an association between smoking cigarettes and mood disorders like depression. Less clear is the direction of this relationship: whether depression causes people to smoke or whether smoking causes depression. There is also research that suggests that perhaps a third factor, possibly genetics, mediates the co-occurrence of smoking and depression. Though the causality remains unclear, smokers quitting may experience negative affectivity and therefore can plan accordingly to help prevent relapse.
Smoking and Mood Disorders
Data from population studies show that patients diagnosed with mood disorders are more likely to smoke compared to the general population. One study in the "Journal of Dual Diagnosis" says that while the smoking prevalence of the U.S. population is about 20 to 25 percent, the prevalence among patients with mood disorders is substantially higher at about 35 to 65 percent. Researchers speculate that smokers self-medicate with nicotine from tobacco to regulate mood.
Smoking and Depressive Symptoms
There is evidence to suggest smoking cigarettes may increase the risk for depressive symptoms. There also seems to be a positive dose-response relationship between increasing levels of nicotine dependence and higher lifetime rates of depression. The findings suggest that the more cigarettes you smoke, and the more nicotine you consume, the higher the risk of developing depressive symptoms.
Genetics and Family History
The "Archives of General Psychiatry" published a discordant twin study among women that examined the causal relationship between smoking and major depression. The study concluded no causal relationship but a third factor--likely familial such as genetics--that mediates the occurrence of both smoking and depression. The findings suggest your family history and environment are more likely to determine whether you smoke and whether you're depressed.
Biological Relationship
Researchers believe chronic nicotine use from tobacco may desensitize brain processes that induce depression. But this is disrupted when a smoker quits, and likely explains why smokers who quit often report symptoms similar to depression. Doctors often prescribe bupropion, a pharmaceutical drug originally developed as an antidepressant, to help smokers quit. As a cessation aide, the antidepressant is used to help smokers regulate negative affect resulting from nicotine withdrawal during cessation.
Quitting and Mood Management
Smokers who are quitting should be advised that withdrawal symptoms such as irritability, low mood and perhaps even depression are common, but negative affectivity resulting from acute nicotine withdrawal is temporary. After the first few weeks of quitting, withdrawal symptoms should subside and the brain chemistry should be back to normal. Often smokers report relapse from stressful situations; smokers planning to quit may increase their success by finding alternative strategies for mood management.
References
- "Journal of Dual Diagnosis"; Biological Basis for the Co-morbidity Between Smoking and Mood Disorders; Yann S. Mineur, Ph.D. and Marina R. Picciotto, Ph.D.; April 2009
- "Archives of General Psychiatry"; Smoking and Major Depression: A Causal Analysis; Kenneth S. Kendler, M.D., Michael C. Neale, Ph.D., Charles J. MacLean, Ph.D.; Andrew C. Heath, DPhil., Lindon J. Eaves, Ph.D., DSc., Ronald Kessler, Ph.D.; January 1993
- "The British Journal of Psychiatry"; Cigarette Smoking and Depression: A Question of Causation; Marcus R. Munafo, Ph.D. and Ricardo Araya, Ph.D.; June 2010
- "The British Journal of Psychiatry"; Cigarette Smoking and Depression: Tests of Causal Linkages Using a Longitudinal Birth Cohort; Joseph M. Boden, Ph.D., David M. Fergusson, Ph.D., and L. John Horwood, M.Sc.; June 2010
- "Archives of General Psychiatry"; Nicotine Dependence, Major Depression, and Anxiety in Young Adults; Naomi Breslau, Ph.D., M. Marlyne Kilbey, Ph.D., Patricia Andreski, M.A.; December 1991
