Cigarette Smoking Gateway to Illegal Drug Use

With the United States currently suffering from more than 400,000 tobacco-related deaths each year, one would think that tobacco alone has enough serious health complications. But a new study from the Johns Hopkins School of Public Health additionally shows that cigarette smoking increases a person's risk of using illegal drugs, which will eventually lead to a slew of entirely new consequences. The study was published in the December issue of the Journal of Addictive Diseases.

To investigate the associations between cigarette smoking and illegal drug use, the researchers analyzed data from the 1994 National Household Survey on Drug Abuse which provided information about the use of illicit drugs, alcohol, and tobacco among members of the non-institutionalized United States civilian population aged 12 or older. The survey data were originally collected through personal visits to the residences of 17,809 respondents.

Results showed that those who had smoked cigarettes were more likely to use illegal drugs. For all age groups combined, the 65.8 percent of participants who had ever smoked were: seven times more likely to have tried marijuana; seven times more likely to have tried cocaine; 14 times more likely to have tried crack; and 16 times more likely to have tried heroin. The results were even more startling when the statistical evidence was sub-divided by age groups. Associations between smoking and illegal drug use were significantly stronger for young people. For instance, people ages 12 to 15 who smoked cigarettes were 44 times more likely to use crack, compared with only a twofold risk in those 50 or older.

"Results of this study deliver a strong cautionary message that those who smoked cigarettes before the age of 15 were up to 80 times more likely to use illegal drugs than those who did not," said lead author Shenghan Lai, MD, MPH, associate research professor, Epidemiology, Johns Hopkins School of Public Health.

Cocaine, in either powder or crack form, was the drug most likely to be used among young cigarette smokers. Because the associations decrease with age, the authors said there is an implication that cigarette smoking is a better predictor for illegal drug use in young people. With the numbers of highschool-aged smokers increasing over the past decade, the results of the present analysis in fact predict an increase in illegal drug use over the next few decades.

The researchers recognize the need for further prospective studies because the data used were not initially taken for the purpose of this study. Also needed, they said, are additional investigations into the causes of associations between cigarette smoking and illegal drug use, such as the roles played by behavioral genetics, developmental psychology, and the ethnography of adolescent drug using patterns.

"Despite the need for further research," says Dr. Lai, "the study does clearly indicate that in the overall population surveyed, early tobacco use at least can be used as a predictor to identify those who will use illegal drugs later on in life."

Funding for this study was provided by the National Institute on Drug Abuse.