Adult smokers with a history of problem drinking who continue smoking are at a greater risk of relapsing three years later compared with adults who do not smoke. Results of the study by researchers at Columbia University’s Mailman School of Public Health and the City University of New York appear online in the journal Alcoholism: Clinical and Experimental Research.

Most adults who have alcohol problems also smoke cigarettes. Yet while treatments for alcohol abuse traditionally require concurrent treatment for problems around illicit substance use, smoking has not generally been part of alcohol or substance use treatment. According to lead author Renee Goodwin, PhD, the thinking in clinical settings has been that asking patients to quit cigarette smoking while they try to stop drinking is “too difficult,” and that continued nicotine dependence would make no difference in the long run.

“Quitting smoking will improve anyone’s health,” says Goodwin, an associate professor in the Department of Epidemiology at the Mailman School of Public Health. “But our study shows that giving up cigarettes is even more important for adults in recovery from alcohol since it will help them stay sober.”

The researchers followed 34,653 adults with a past alcohol use disorder enrolled in the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC) who were assessed at two time points, three years apart, on substance use, substance use disorders, and related physical and mental disorders.

Only those with a history of alcohol use disorders according to DSM-IV criteria were included in the final sample. Daily smokers and nondaily smokers had approximately twice the odds of relapsing to alcohol dependence compared with nonsmokers. The relationships held even after controlling for factors, including mood, anxiety, illicit drug use disorders, and nicotine dependence.

It’s unclear why smoking makes alcohol relapse more likely, but the study’s authors point to past research on the behavioral and neurochemical links between smoking and alcohol, and the detrimental effects of smoking on cognition.