Contacts: Dieter J. Meyerhoff, Dr.rer.nat
University of California - San Francisco School of Medicine
Edith V. Sullivan, Ph.D.
Stanford University School of Medicine
Alcoholism: Clinical & Experimental Research
Abstinence may make the brain grow stronger
- Chronic alcohol abuse leads to structural brain damage.
- The damage includes loss of gray matter in the cortex and loss of white matter throughout the brain.
- The greatest tissue loss occurs in the frontal lobe and cerebellum.
- Prolonged abstinence from alcohol appears to allow some reversal of structural brain damage.
Substantial research has demonstrated that chronic alcohol abuse leads to structural brain damage, especially to white matter, and primarily in the frontal lobes and cerebellum. Researchers have wanted to know for quite some time to what extent these effects may be reversible with abstinence from alcohol. A study in the November issue of Alcoholism: Clinical & Experimental Research uses quantitative neuroimaging to reveal that prolonged abstinence may lead to partial reversal of structural brain damage, which suggests that brain function can improve with abstinence.
"We wanted to know if abstinence from alcohol reverses the kind of structural and metabolic abnormalities that have been demonstrated by previous studies," said Dieter J. Meyerhoff, associate professor of radiology at the University of California - San Francisco School of Medicine and lead author of the study. "We also wanted to know in what specific brain regions and tissue types (gray or white matter) damage would be reversed with prolonged abstinence."
Meyerhoff, who is based at the San Francisco Veterans Affairs Medical Center, and his colleagues compared two groups. One group comprised alcoholics (with an average age of 46 years) who had already undergone treatment for their alcoholism and had been abstinent for an average of two years at the time of study.
The second group comprised individuals who were heavy drinkers at the time of study and had never been treated for their drinking. The current drinkers were matched in drinking severity (average monthly alcohol use over lifetime, and duration of alcohol use) to the prior drinking patterns of the abstinent alcoholics.
A healthy control group was not included because the study's intent was to measure the effects of abstinence from chronic drinking on alcohol-induced injury. All participants underwent magnetic resonance imaging (MRI) and proton magnetic resonance (MR) spectroscopic imaging of the brain.
"These are non-invasive methods," explained Meyerhoff, "which allow taking a 'snapshot' of the structural and metabolic integrity of all parts of the brain. As opposed to computed tomography scans, MRI can distinguish between gray and white matter tissue, which is important when we want to talk about the functional significance of brain damage in alcoholism. In addition, we used a localization approach that allowed us to investigate structural and metabolic brain changes in relatively small yet anatomically well-defined brain regions."
They found that the abstinent alcoholics had a greater volume of white matter in their frontal lobes than currently heavy drinkers did, but not in other parts of the brain. White matter volume was greatest in those alcoholics who had been abstinent for the longest time. In addition, the amount of white matter lesions in the abstinent alcoholics was smaller than in the current drinkers in most of the brain regions investigated. Finally, the volume of gray matter in the abstinent alcoholics was greater in some but not all regions of the frontal lobes.
"These results suggest reversal of structural abnormalities in some brain regions of abstinent alcoholics," said Meyerhoff, "and persistent structural damage in other brain regions. We still need to learn, however, what this means for the individual's brain function."
What these findings provide in practical terms, said Edith Sullivan, associate professor of psychiatry at Stanford University School of Medicine, is hope for the recovering alcoholic and encouragement to remain sober.
"We know that alcohol abuse can cause extensive damage to the brain," she said. "This can include volume deficits in cortical gray matter, which are neural cell bodies, as well as in white matter, which are the fibers that are extensions of the cell bodies and that connect cells. The regions most clearly affected are the frontal lobes.
Additional brain structures affected are the corpus callosum, the large band of white matter fibers that connect the two cerebral hemispheres, the anterior aspect of the hippocampus and the mammillary bodies, brain structures that engage in consolidation of new memories, and the cerebellum, the 'little brain' that is critical to postural stability, motor timing, and motor learning as well as certain components of cognitive functioning. The UCSF study suggests that the recovering alcoholic group, despite their older age, can experience a significant reversal of white matter abnormality with prolonged abstinence."
Sullivan said that future research needed to focus on longitudinal studies, using different modalities of brain imaging, that follow alcoholics from early detoxification through periods of sobriety and relapse. She added that these studies need to take into account nutritional factors, withdrawal symptoms, and functional outcomes in alcoholic men and women of all ages.
This is in fact what Meyerhoff and his colleagues have in the works: longitudinal studies of alcoholics who undergo treatment for their drinking problem. "These studies are ongoing and include structural and metabolic MR studies integrated with careful assessment of neuropsychological functioning. Both abstainers and relapsers are examined to assess postulated improvement with successful abstinence and postulated status quo or further deterioration with relapse." Although more data have yet to be collected and analyzed, said Meyerhoff, "it appears that even after many years of heavy drinking, the brain has the capacity to repair at least some of the structural damage that has occurred."
Co-authors of the Alcoholism: Clinical & Experimental Research paper included: Joseph O'Neill of the Department of Psychiatry at the University of California - Los Angeles School of Medicine, and Valerie A. Cardenas of the Department of Radiology at the University of California - San Francisco School of Medicine.
The study was funded by the Public Health Service.