Smoking makes it harder for brains of problem drinkers to recover from alcohol abuse, according to a new study.
Previous research has shown that alcohol-dependent individuals (ALC) sustain neurocognitive impairment even after detoxification.
The new study examined specific domains of cognitive recovery in conjunction with smoking status.
Researchers found that smoking status influenced the rate and level of neurocognitive recovery during eight months of abstinence in the ALC group.
"There have been few longitudinal studies that have specifically studied the effects of cigarette smoking on cognitive recovery in ALC during abstinence," said Timothy C Durazzo, associate professor in the department of radiology and biomedical imaging at the University of California San Francisco, and corresponding author for the study.
Durazzo and his colleagues examined a total of 133 ALC participants - 30 had never smoked, 28 were former smokers, and 75 were active smokers - as well as 39 never-smoking "control" participants.
Approximately 89 per cent of the participants were male. All of the participants were given standardised measures of auditory-verbal and visuospatial learning and memory, processing speed, and working memory.
Assessments after one week, four weeks, and eight months of abstinence for the ALC group allowed a comparison of the rates of neurocognitive changes from one to four weeks versus one to eight months of abstinence.
The controls completed a baseline assessment and a follow-up approximately nine months later.
"We found that, overall, the ALC as a group showed the greatest rate of recovery on most abilities during the first month of abstinence," said Durazzo.
"Over eight months of sustained abstinence from alcohol, active-smoking ALC showed poorer recovery than never-smoking ALC on measures of learning, and both former-smoking ALC and active-smoking ALC recovered less than never-smoking ALC on processing speed measures.
"In addition, after eight months of abstinence, active-smoking ALC performed worse than both controls and never-smoking ALC on most measures, former-smoking ALC performed worse than never-smoking ALC on several tests, but never-smoking ALC were not different from controls on any measure.
"Overall, the findings indicated never-smoking ALC showed full recovery on all measures after 8 months of sustained abstinence from alcohol," Durazzo said.
The study will be published in the journal Alcoholism: Clinical & Experimental Research.
