New research suggests chronic smoking, excessive alcohol consumption, and increasing age are all associated with increased oxidative damage to brain tissue.
Experts say the study is the first to look at the effects of smoking and age on neurocognition in people seeking treatment for alcohol dependency.
Researchers say the findings are important because treatment for alcohol use disorders is more effective if a person actively understands and adopts the interventions. Multiple factors may impede cognition during early abstinence including chronic cigarette smoking and increasing age.
In the study, researchers discovered alcohol dependent (AD) individuals who currently smoke show more problems with memory, ability to think quickly and efficiently, and problem-solving skills than those who don’t smoke, effects which seem to become exacerbated with age.
Study results will be published in Alcoholism: Clinical & Experimental Research and are currently available at Early View.
“Several factors — nutrition, exercise, comorbid medical conditions such as hypertension and diabetes, psychiatric conditions such as depressive disorders and post-traumatic stress disorder, and genetic predispositions — may also influence cognitive functioning during early abstinence,” explained Timothy C. Durazzo, Ph.D., corresponding author for the study.
“We focused on the effects of chronic cigarette smoking and increasing age on cognition because previous research suggested that each has independent, adverse affects on multiple aspects of cognition and brain biology in people with and without alcohol use disorders.
“This previous research also indicated that the adverse effects of smoking on the brain accumulate over time. Therefore, we predicted that AD, active chronic smokers would show the greatest decline in cognitive abilities with increasing age.”
The interactive effects of smoking and other drug use on cognitive functioning among those with alcohol dependence are largely unknown.
“This is problematic because many heavy drinkers also smoke. Furthermore, in treatment programs for alcoholism, the issue of smoking may be largely ignored,” said Alecia Dager, Ph.D., associate research scientist in the department of psychiatry at Yale University.
Experts believe the current study provides important insights for treatment programs.
First, individuals with AD who also smoke may have more difficulty remembering, integrating and implementing treatment strategies. Second, there are clear benefits for thinking skills as a result of quitting both substances.
Durazzo and his colleagues compared the neurocognitive functioning of four groups of participants, all between the ages of 26 and 71 years of age: never-smoking healthy individuals as controls (n=39); and one-month abstinent, treatment-seeking AD individuals, who were never-smokers (n = 30), former-smokers (n = 21) and active-smokers (n = 68).
Researchers assessed cognitive efficiency, executive functions, fine motor skills, general intelligence, learning and memory, processing speed, visuospatial functions, and working memory.
“We found that, at one month of abstinence, actively smoking AD [individuals] had greater-than-normal age effects on measures of learning, memory, processing speed, reasoning and problem-solving, and fine motor skills,” said Durazzo.
“AD never-smokers and former-smokers showed equivalent changes on all measures with increasing age as the never-smoking controls. These results indicate the combination of alcohol dependence and active chronic smoking was related to an abnormal decline in multiple cognitive functions with increasing age.”
“These results indicate the combined effects of these drugs are especially harmful and become even more apparent in older age,” said Dager.
“In general, people show cognitive decline in older age. However, it seems that years of combined alcohol and cigarette use exacerbate this process, contributing to an even greater decline in thinking skills in later years.”