Alcoholics who smoke develop more problems with memory, ability to think quickly and efficiently, and problem-solving skills than those who don't smoke, a first-of-its-kind study has found.
The study looked at the interactive effects of smoking status and age on neurocognition in treatment-seeking alcohol dependent (AD) individuals.
"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," said Timothy C Durazzo, 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," said Durazzo, assistant professor in the department of radiology and biomedical imaging at the University of California San Francisco.
"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," he said.
"This study provides evidence of greater cognitive difficulties in alcoholics who also smoke, which could offer important insights for treatment programmes," said Alecia Dager, associate research scientist in the department of psychiatry at Yale University.
"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," Dager said.
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 or "controls"; and one-month abstinent, treatment-seeking AD individuals, who were never-smokers, former-smokers and active-smokers.
"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," Durazzo said.
