Center for Addiction Medicine

11/06/2007 - Smoking Affects Boilogy and Function of the Brain of those with Alcohol Use Disorders

Although smoking rates in the general population of the United States has decreased over the last three decades, smoking prevalence remains high especially among the individuals with alcohol and substance abuse disorders.

A recent study in Alcohol and Alcoholism sought to determine the adverse effects of chronic smoking on the brain in those undergoing treatment for alcohol use disorders.. The research was designed to prompt discussions about treatment strategies for comorbid alcoholism and cigarette smoking.

NEUROBIOLOGICAL AND NEUROCOGNITIVE CONSEQUENCES OF CHRONIC SMOKING IN ALCOHOL USE DISORDERS

Cross-sectional Quantitative MR Studies in Alcohol Use Disorders

Researchers quantified brain structure with high-resolution MRI and found significant smoking effects for parietal, temporal and occipital gray matter, where smokers demonstrated less gray matter in these regions than non-smokers. Significant smoking effects were observed for the temporal white matter and a trend for frontal white matter were observed, with greater white matter volumes in smokers compared to non-smokers. Both chronic, excessive alcohol consumption and chronic smoking were associated with significant neurocortical gray matter loss.

Quantitative Brian Blood Flow

Regional neocortical blood flow was compared using a non-invasive pulsed arterial spin labeling method that imaged primarily the frontal and parietal lobes. Multivariate analyses indicated significant differences for perfusion in both frontal and parietal gray matter. Frontal gray matter perfusion in smoking alcoholics was 18% lower than non-smoking alcoholics. Parietal gray matter perfusion in smoking alcoholics was inversely correlated with the number of cigarettes smoked per day.

Cross-sectional Neurocognitive Studies in Alcohol Use Disorders

Evaluation of neurocognitive skills of smoking and non-smoking alcoholics revealed that non-smoking alcoholics were superior to smoking alcoholics on measure of auditory-verbal learning and memory, processing speed, cognitive efficiency and static postural stability. In smoking alcoholics, longer smoking duration was negatively correlated with executive skills, visuospatial learning, general cognitive efficiency and static postural stability.

EFFECTS OF CHRONIC SMOKING ON NEUROBIOLOGICAL AND NEUROCOGNITIVE RECOVERY DURING ALCOHOL ABSTINENCE

Quantitative Morphometric MRI in Treatment-seeking Alcoholics

Using the deformation based morphometry brain shape analysis method; researchers observed that tissue volume recovery in alcoholics occurs primarily in the frontal white matter, subcortical nuclei, pons, cerebellum, hippocampi and sections of the corpus callosum. Analysis clearly indicated that chronic cigarette smoking influenced the volume recovery during sustained abstinence from alcohol. Specifically, these analyses indicated that abstinent smoking alcoholics had significantly lower tissue volume recovery rate than abstinent non smoking alcoholics in the left anterior hippocamspus/ amygdale region, with trends for lower volume recovery rate smoking alcoholics in frontal and temporal gray matter.

Longitudinal Metabolite Imaging in Treatment-Seeking Alcoholics

Overall, smoking alcoholics demonstrated numerically smaller and fewer regional increases of N-acetylaspartate and choline concentration over one month of abstinence than non-smoking alcoholics. The non-smoking alcoholic group showed many significant relationships between changes of metabolite levels and neurocognition, attesting to the functional relevance of brain metabolite changes.

Over one month of sobriety, medial temporal lobe N-acetylaspartate and choline levels in non-smoking alcoholics significantly increased and normalized. However, in smoking alcoholics, N-acetylaspartate and choline concentrations did not change significantly and remained depressed. Hippocampal volumes significantly increased in both groups over one month abstinence from alcohol, but increasing volumes correlated with improved visuospatial learning only in non-smoking alcoholics.

CONCLUSIONS

Evidence from the study suggests chronic cigarette smoking adversely affects both brain neurobiology and neurocognition in alcohol use disorders, thus contributing to the growing body of literature linking chronic smoking to brain injury and dysfunction

If chronic cigarette smoking does indeed modulate brain neurobiology and neurocognition, it is possible that smoking and non-smoking alcoholics may differ in the nature or extent of their response to pharmacological and/or behavioral interventions designed to promote abstinence from alcohol.

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