Teenagers who are heavy smokers are more likely to suffer from depression than their peers, according to new research.
Teenagers who smoked more than 20 cigarettes a day for six months were more likely to have more depressive symptoms than teenagers who smoked less or not at all. Those who are heavy smokers reported feeling lonely and helpless, seeing themselves as failures more frequently than those who smoke less. The researchers said those symptoms are associated more with depression.
The study was done at the University of Alabama at Birmingham by psychologist Michael Windle and his research assistant and wife, Rebecca C. Windle.
The study looked at the depression levels and smoking habits of 1,218 teenagers in western New York for two years. The average age of those studied was 15. The research was published in the April issue of the Journal of Consulting and Clinical Psychology, a periodical of the American Psychological Association.
In addition to smoking levels, Windle and researchers measured students' family involvement and support, delinquent behavior, family history of smoking and their use of alcohol and illicit drugs.
Earlier studies showed a link between depression and smoking, but the Windles' research ruled out factors such as behavior and family history that could cause depressive symptoms. They also studied the participants for a longer time, Windle said.
Smoking and depression appear to reciprocally influence each other, the Windles said.
It could be that teenagers or even adults with high levels of depression significantly increase cigarette smoking in attempts to alleviate their depressive symptoms, the authors said. Because nicotine is a stimulant, it makes a person feel better for a while, but the body requires more nicotine over time to continue its effect, Michael Windle said.
"In adolescence there are a lot of changes that make them more subject to depression," he said. "They start smoking to self-medicate."
Windle said when a teen stops smoking, depression can follow.
"There is an increase of depression that leads to a tendency to increase smoking and then an increase in depression," he said. "It's not just willpower to stop. ... There's a lot of things going on here."