Genetic Link Found Between Smoking and Depression

A Saint Louis University School of Public Health researcher believes there may a genetic link between smoking and depression.

Dr. Qiang John Fu and his team analyzed 3,360 pairs of middle-aged, mostly white twins who served in the military during the Vietnam War. About 55 percent were identical twins, who possess the same genetic makeup, and the rest were fraternal twins who shared half their genes. The researchers compared the answers given by the twins and used a mathematical model to estimate the genetic and environmental influences on nicotine addiction and major depression.

The team found that both major depression and nicotine dependence were highly genetically correlated with conduct disorder, which is characterized by extreme rebellious behavior, such as vandalism, running away from home and fighting.

Dr. Fu believes this shows a genetic reason why smoking and depression often occur together and that the findings could be used to predict who will be prone to depression and nicotine addiction.

The study appeared in the June issue of Twin Research and Human Genetics.