According to a Duke University study, even small amounts of alcohol increase the pleasurable effects of nicotine, which leads people to smoke more when they're drinking alcohol.

The study, published in a recent issue of Nicotine and Tobacco Research, found new insight into the interaction between alcohol and nicotine and could help in the development of ways to help people quit smoking.

Alcohol enhanced the rewarding effects of nicotine
Researchers followed 48 regular smokers who were given either alcoholic or placebo beverages and either regular or nicotine-free cigarettes. According to ratings done by the volunteers, alcohol enhanced many of the rewarding effects of nicotine, including satisfaction and the calming effects of nicotine.

However, subjects did not experience the same positive response with alcohol when they smoked nicotine-free cigarettes. The scientists concluded that this indicates nicotine itself is the critical ingredient in the smoking-drinking interaction and not other aspects of smoking.

Low dose of alcohol was sufficient
A relatively low dose of alcohol—below that required to induce any measurable euphoria—was enough to increase participants' enjoyment of nicotine significantly.

The findings offer a physiological explanation for why people smoke more when they are in bars. It may also help explain why alcoholics tend to smoke more than non-drinkers and why smokers are more likely to be alcoholics. Also, the study’s authors cite the findings as a key to why it is common for people who have quit smoking to relapse when they drink.

Reference:

1. S. A. McKee; Hinson, R., Petrelli, P., Rounsaville, D., “Survey of Subjective Effects of Smoking While Drinking Among College Students,” Nicotine and Tobacco Research, 111 – 117: 6: 1: 2004.