208 



Chart 9 



The attributable risks used for this study may understate the impact of substance abuse in 

 precipitating some diseases because they were primarily based upon only one substance. People 

 who abuse multiple substances have a much higher risk of getting these diseases than those who 

 abuse only one substance. Our PARs do not take into account the synergistic effect of the abuse 

 of multiple substances in part because epidemiologic research has not thoroughly assessed the 

 synergistic effects of poly-substance use, and because prevalence rates for people who abuse 

 more than one substance - on Medicaid or in the general population - are not available. 



Chart 9 highlights the synergistic effect of dual-drug use: heavy drinking combined with heavy 

 smoking dramatically increases the risk of throat cancer. People who smoke and drink are 135 

 times more likely to get throat cancer than those who abstain from both. In addition, they are 

 27 times more likely to get this disease than people who only smoke. This is also true for oral 

 cavity cancer. Those who drink and smoke are 24 times more likely to contract oral cavity 

 cancer than those who do not smoke or drink; they are 10 times more likely to contract this 

 cancer than those who only drink. 



-36- 



