Depression, alcohol use, and marijuana use are all more prevalent among adolescents who smoke, according to a report from the National Center on Addiction and Substance Abuse (CASA).

Reuters reported Oct. 23 that the report, which analyzed previously published data and surveys, found that 59 percent of smokers aged 12 to 17 also drank alcohol, compared to 11 percent of nonsmokers. Current cigarette smokers in this age group also were 13 times more likely to smoke marijuana, and also have a higher risk of depression and anxiety disorders.

Some researchers speculate that smoking may prime the adolescent brain for other types of addictive behaviors. "Teenage smoking can signal the fire of alcohol and drug abuse or mental illness like depression and anxiety," said CASA head Joseph Califano. "There's no question that early teenage smoking is linked to these other things. Now whether it's causing it or not, I think the jury is probably still out on that."