Smoking May Interfere With Alcoholics' Neurocognitive Recovery During Abstinence

"There are several possible explanations for the concurrent use of alcohol and tobacco products," said Timothy C. Durazzo, assistant adjunct professor in the department of radiology at the University of California San Francisco, and corresponding author for the study. "Nicotine and alcohol may enhance each other's rewarding properties; nicotine may decrease some of alcohol's negative effects on cognition and motor incoordination; paired use of nicotine and alcohol may produce a strong association between the two substances such that the use of one leads to cravings for the other; and there may exist a genetic vulnerability for concurrent active cigarette smoking and alcohol dependence."

Durazzo added that previous research had shown that chronically smoking alcoholics demonstrate poorer performance in multiple areas of cognitive functioning than non-smokers when they are still actively drinking or after a short period of sobriety. "However, it was unknown if non-smoking alcoholics and alcoholics who continued to smoke during abstinence would show comparable levels of recovery after a sustained period of sobriety," he said.

Study authors recruited three groups: 13 non-smoking recovering alcoholics (12 males, 1 female), 12 actively smoking recovering alcoholics (11 males, 1 female), and 22 non-smoking light-drinking "controls" (20 males, 2 females). The researchers examined neurocognitive changes that occurred in the two recovering-alcoholic groups during six to nine months of abstinence from alcohol, comparing their neurocognitive performance with that of the controls.

"Non-smoking alcoholics showed a significantly greater level of recovery than smoking alcoholics in the areas of mental efficiency, higher-level reasoning and problem-solving, visual-spatial processing skills, and working or short-term memory," said Durazzo. "Although smoking alcoholics in the study improved significantly in auditory-verbal memory and processing speed over six to nine months of abstinence from alcohol, the level of their recovery was not greater than the non-smoking alcoholics. It is also of note that in the smoking alcohol group, those with greater nicotine dependence and longer smoking histories showed less recovery in several areas of functioning."

"In short, abstinent alcoholics without a history of cigarette smoking achieved better recovery of critical mental functions during the first six to nine months of sustained sobriety," said Sara Jo Nixon, a professor in the department of psychiatry at the University of Florida. "[These] differential outcomes demonstrate the importance of considering the behavioral impact of continued cigarette smoking among alcoholics on long-term recovery of function."

Durazzo concurred. "Previous research on neurobiological and cognitive recovery from chronic alcoholism has not considered the potential impact of cigarette smoking on recuperation," he said. "Furthermore, most research investigating the health consequences of chronic cigarette smoking has focused on increased risk for various forms of cancer and the cardiovascular, cerebrovascular, pulmonary ramifications. Given that the mortality associated with cigarette smoking is nearly four times greater than the mortality related to alcohol-induced diseases, and given our findings ... perhaps chronic smokers entering treatment for substance abuse and alcoholism should consider concurrent participation in a smoking-cessation program.""This study did not include a group of alcoholics who had quit smoking at the time of discontinuing alcohol use," noted Nixon, "but these data suggest this would be an important study. It is [also] important that the current study was almost exclusively male. Given the growing literature regarding female smokers, additional studies including women should be conducted. Finally, as the authors note, the observed differences are not likely associated with nicotine, per se. Rather, they are associated with exposure to the many toxins in smoke. This distinction is critical in considering individual options for nicotine cessation."

"Even though our results should be considered preliminary," said Durazzo, "they suggest that consideration of smoking status is relevant to the assessment of cognitive recovery. More generally, chronic smoking may impact neurocognition in other conditions where is it a prevalent behavior, such as schizophrenia-spectrum and mood disorders. Further research is imperative."

Results are published in the July issue of Alcoholism: Clinical & Experimental Research.