Alcoholism and the brain: an overview

Alcohol Research & Health, Spring, 2003 by Marlene Oscar-Berman, Ksenija Marinkovic

IMPLICATIONS FOR TREATMENT

Because alcoholism is associated with diverse changes to the brain and behavior, clinicians must consider a variety of treatment methods to promote cessation of drinking and recovery of impaired functioning. With an optimal combination of neuropsychological observations and structural and functional brain imaging results, treatment professionals may be able to develop a number of predictors of abstinence and relapse outcomes, with the purpose of tailoring treatment methods to each individual patient. Neuroimaging methods have already provided significant insight into the nature of brain damage caused by heavy alcohol use, and the integration of results from different methods of neuroimaging will spur further advances in the diagnosis and treatment of alcoholism-related damage. Clinicians also can use brain imaging techniques to monitor the course of treatment because these techniques can reveal structural, functional, and biochemical changes in living patients across time as a result of abstinence, therapeutic interventions, withdrawal, or relapse. For example, functional imaging studies might be used to evaluate the effectiveness of drugs such as naltrexone on withdrawal-induced craving. (Naltrexone is an anticraving medicine that suppresses GABA activity.) Additionally, neuroimaging research already has shown that abstinence of less than a month can result in an increase in cerebral metabolism, particularly in the frontal lobes, and that continued abstinence can lead to at least partial reversal in loss of brain tissue (Sullivan 2000). Neuroimaging indicators also can be useful in prognosis, permitting identification and timely treatment of patients at high risk for relapse.

SUMMARY

Alcoholics are not all alike; they experience different subsets of symptoms, and the disease has different origins for different people. Therefore, to understand the effects of alcoholism, it is important to consider the influence of a wide range of variables. Researchers have not yet found conclusive evidence for the idea that any one variable can consistently and completely account for the brain deficits found in alcoholics. The most plausible conclusion is that neurobehavioral deficits in some alcoholics result from the combination of prolonged ingestion of alcohol, which impairs the way the brain normally works, and individual vulnerability to some forms of brain damage. Characterizing what makes alcoholics "vulnerable" remains the subject of active research.

In the search for answers, it is necessary to use as many kinds of tools as possible, keeping in mind that specific deficits may be observed only with certain methods, specific paradigms, and particular types of people with distinct risk factors. Neuroscience provides sensitive techniques for assessing changes in mental abilities and observing brain structure and function over time. When techniques are combined, it will be possible to identify the pattern, timing, and distribution of the brain regions and behaviors most affected by alcohol use and abuse. Electromagnetic methods (ERP and MEG) specify the timing of alcohol-induced abnormalities, but the underlying neural substrate (i.e., the anatomical distribution of the participating brain areas) cannot be unequivocally evaluated based on these methods alone. Conversely, the hemodynamic methods (fMRI, PET, and SPECT) have good spatial resolution but offer little information about the sequence of events. Drawing on the respective advantages of these complementary methods, an integrated multimodal approach can reveal where in the brain the critical changes are occurring, as well as the timing and sequence in which they happen (Dale and Halgren 2001). Such confluence of information can provide evidence linking structural damage, functional alterations, and the specific behavioral and neuropsychological effects of alcoholism. These measures also can determine the degree to which abstinence and treatment result in the reversal of atrophy and dysfunction.