How Smoking Causes Depression

Cigarette smoking is associated with higher rates of depression, but it is unclear whether smoking causes depression or if preexisting depression leads to higher rates of smoking.

Prevalence

• Approximately 50 percent to 70 percent of Americans with major depression are smokers--a rate two to three times higher than that of the general population.

Functions

• Immediately after smoking, levels of many neurotransmitters associated with mood elevation, including norepinephrine, dopamine and acetylcholine, increase.
  However, they eventually decrease, typically to levels lower than prior to smoking, which can lead to feelings of depression and nicotine cravings.

Explanations

• Smoking might be a form of self-medication for people with depression, but smoking might actually exacerbate symptoms of depression, which in turn can lead to more smoking. Certain genes might be responsible for both increasing likelihood of nicotine addiction and depression.

Considerations

• Even though a link between depression and smoking has been identified, it does not necessarily mean that smoking causes depression. An alternative explanation is that depressed people are more likely to smoke and increase smoking rates when feeling most depressed.

Cessation

• Smoking cessation commonly leads to symptoms of depression, including depressed mood, difficulty concentrating, irritability, poor sleep and anxiety.