In 1998, a group of alcohol researchers proposed an "alcoholic threshold," suggesting that neuropsychological (NP) deficits or damage were detectable only if chronic alcohol abuse equaled or exceeded 10 years. A study recently published in Alcoholism: Clinical & Experimental Research has contradicted that claim, finding no support for a "threshold" theory.
"There’s no question that alcohol, in the absence of nutritional deficits, can produce toxic changes in the brain," said William W. Beatty, lead author of the more recent study and professor of psychiatry and behavioral sciences at the University of Oklahoma Health Sciences Center. "The idea of a threshold, however, implies that there’s some point where there’s no risk, and that’s just not true."
Neuropsychological or NP deficits, the ‘barometer’ for both studies, refer to negative changes that can occur in the brain as a result of chronic or long-term, heavy drinking. These deficits can occur in the individual’s ability to reason (both verbally and nonverbally), memory and learning capacities (both verbally and nonverbally), and visuospatial perception and perceptual motor skills such as reproducing color-specific block designs. Although these skills and the tests that measure their presence may seem simplistic to many people, the cognitive abilities that they represent are imperative for daily tasks such as driving a car or even remembering where you placed the keys.
"Testing for neuropsychological deficits is very important for both physicians and patients," said Edith V. Sullivan, associate professor of psychiatry at Stanford University School of Medicine. "Mild to moderate deficits in certain types of cognitive activities might not necessarily be picked up on in a typical physical examination. Yet these cognitive deficits are particularly important for the patient to recognize in order to understand his scope and limits of what he can do in a day, in a job and for the rest of his life." She added: "They’re also very important to help the rehabilitation therapist guide rehabilitative efforts."
Beatty’s study compared the test results of recovering alcoholics who were recruited from drug rehabilitation centers in Oklahoma City with those of non-alcoholics. Specifically, Beatty and his co-researchers looked at alcoholics who had been chronic drinkers for up to nine years, or for 10 years or more. Although there was enormous variation from one alcoholic to another, said Beatty, overall the alcoholics performed worse on the tests than the non-alcoholics. There were no differences, however, between those who had abused alcohol for more, or less, than 10 years.
"This study has critically important clinical and rehabilitative ramifications," said Sullivan. "People who are not yet heavy drinkers should be warned that their cognitive and motor facilities are really pretty fragile and are not going to withstand many years of heavy drinking. These people can’t drink with impunity."
"I don’t think there’s any debate that chronic alcoholism can lead to brain dysfunction," said Beatty, "but there is still uncertainty regarding when it happens, why it happens, and how some people can drink like a proverbial fish and still remain functional."
Beatty’s study may have answered one question, but it also raised several more. For example, the study found no relationship between years of alcoholic drinking and severity of impairment. Some of the alcoholics in the study who had been drinking for three or four years demonstrated the same brain deficits as those who had been drinking for 30 or more years. "It has always been assumed that the same familial relationships that govern susceptibility to becoming an alcoholic would also be involved in vulnerability to alcohol-produced deficits in the brain. But our research causes us to say that maybe there are separate vulnerability factors."
In other words, two different vulnerabilities may exist. The first is a vulnerability (such as a genetic predisposition) to developing an alcohol dependency. The second is a vulnerability to developing brain damage once heavy drinking has commenced. In either case, the individual is at high risk; what remains to be answered is how much of a risk, and how quickly degeneration will commence once alcohol abuse begins.
Despite what vulnerabilities to alcohol dependency and/or brain damage may exist, Sullivan’s work has demonstrated that alcoholic brains can recover to various degrees once drinking has ceased.
"One thing that’s extremely important to understand is that if it took an alcoholic four years to become an alcoholic, it may take him that long to undo all the brain damage that he has incurred," she noted. "Recovery doesn’t take place in just three days of abstinence, it doesn’t take place after a 30-day inpatient treatment, it doesn’t take place after six months. It carries on and, possibly, ends up being a life-long rehabilitative effort."
Funding for this Addiction Science Made Easy project is provided by the Addiction Technology Transfer Center National Office, under the cooperative agreement from the Center for Substance Abuse Treatment of SAMHSA.
Articles were written based on the following published research:
Beatty, W.W., Tivis, R., Stott, H. D., Nixon, S. J., & Parsons, O. A. (1999, February). Neuropshychological deficits in sober alcoholics: Influences of chronicity and recent alcohol consumption. Alcoholism: Clinical and Experimental Research, 24(2), 149-154.