As if it is not tough enough for illicit drug users to kick their habit, cigarette smoking seems to make it even rougher. Or so suggest several studies reported in the February Experimental and Clinical Psychopharmacology.

In one study Dominick Frosch, a doctoral student at San Diego State University, and his colleagues set out to investigate whether cigarette smoking was linked to a return to drug use in persons already known to have used illicit drugs in the past.

They studied 32 persons who were on methadone to kick heroin addiction. Ten were nonsmokers, 11 were chippers (individuals who smoke cigarettes on a regular basis, yet show no signs of nicotine dependence), and 11 were heavy smokers. The subjects were given urine tests every day for seven consecutive days to see whether their urine contained a breakdown product of nicotine, a breakdown product of heroin, or one of cocaine. This way the investigators could determine whether and how much they were smoking and whether they had resumed using heroin or cocaine in spite of methadone maintenance. In other words, if urine levels of either heroin or cocaine were higher on one day than they had been on the previous day, then a relapse was indicated.

As the researchers expected, there was a direct correlation between renewed illicit drug use and cigarette smoking: Only 14.3 percent of nonsmokers started using heroin, yet 36.4 percent of chippers did, and 55.8 percent of heavy smokers did. Similarly, none of the nonsmokers commenced using cocaine, whereas 27.9 percent of the chippers and 53.2 percent of the heavy smokers did (see graph).

In another study Stephen J. Heishman, Ph.D., of the intramural research division of the National Institute on Drug Abuse (NIDA) in Baltimore and his coworkers exposed 18 cigarette smokers, a number of whom also used cocaine, heroin, or marijuana, to imagery scripts. Some of the scripts were neutral toward smoking, whereas the others encouraged it. At the end of each script, subjects filled out questionnaires about whether they craved tobacco and whether they craved their drug of choice. As the investigators anticipated, the scripts promoting smoking heightened subjects’ desire for tobacco, and their urge for tobacco was linked with their desire for their drugs of choice.

"These findings," Heishman contended, "may have implications for the concurrent treatment of tobacco dependence and other drug dependencies."

Frosch holds a similar opinion: "These findings provide compelling reasons for widespread implementation of smoking-cessation programs for methadone-maintained opiate abusers, as the benefits of smoking cessation may extend to other drug use."

Alan I. Leshner, Ph.D., director of NIDA in Bethesda, Md., said that the studies "add very strong behavioral evidence to other research that suggests common characteristics and interactions between tobacco use and opiate and cocaine use. They also suggest that smoking-cessation programs should be offered as part of other drug treatment programs."