The link between depression and smoking develops, it seems, as a cycle that feeds on its own negativity. A genetic link may exist between smoking and depression Each individual is a result of both behavioral and genetic influences. Researchers have begun to test the many ways that genetics play a role in smoking addiction. The possibility that there are important genetically determined differences in people's susceptibility to drug use is supported in numerous studies. Since nicotine is now recognized as an addictive drug, it follows that individuals may also differ in their nicotine susceptibility.
Studies conducted with twins offer the most compelling evidence of genetic influences.
In a recently published report in The New England Journal of Medicine , Dr. Dorit Carmelli and fellow researchers at the Health Sciences Program in Menlo Park, California, discovered moderate genetic influences on lifetime smoking practices. The data also suggest genetic influences on the ability to quit smoking. Dr. Kenneth S. Kendler, a psychiatric geneticist at the Medical College of Virginia, is conducting studies among fraternal and identical twins. He seeks to assess more specifically the genetic interrelatedness of smoking and depression. These researchers are among the pioneering investigators of this intriguing connection.