- "Executive functions" are those capacities, most commonly linked to the frontal cortex, that guide complex behavior over time through planning, decision-making and response control.
- A new study has found that certain cognitive components of executive functioning are compromised early in abstinence.
- These results have implications for the development of new strategies used early in treatment.
Years of heavy alcohol consumption are known to impair abstract thinking, cognitive flexibility and persistence, and inhibition of competing responses. These abilities are among those generally referred to as "executive functions," cognitive operations linked to the frontal cortex that guide complex behavior over time through planning, decision-making and response control. Findings published in the September issue of Alcoholism: Clinical & Experimental Research indicate that several domains of executive functioning are significantly compromised early in abstinence, a time during which patients are currently required to draw upon their cognitive abilities as part of the treatment process.
"The term 'executive functioning' is a business analogy, where the executive monitors all of the different departments so that the company/brain/person can move forward in as efficient and effective a way as possible," said corresponding author H. Scott Swartzwelder, professor of psychiatry at Duke University Medical Center and a senior research career scientist at the Durham VA Medical Center. "So, in terms of real-world activity, executive functioning has everything to do with who we are, how we organize our lives, and how we plan and then execute those plans."
"Executive functions are very, very important to everyday living," added Marlene Oscar Berman, professor of neurology, psychiatry, and anatomy & neurobiology at Boston University Medical School, and research career scientist at the Boston Veteran Affairs Healthcare System. "They are defined differently by different theorists and researchers. Most agree, however, that executive functions are human qualities, including self-awareness, that allow us to be independent individuals with purpose and foresight about what we will do and how we behave. Common executive abilities include judgment, problem solving, decision making, planning, and social conduct, and depend upon many of our cognitive abilities such as attention, perception, memory, and language."
"Alcohol affects executive functioning both acutely and chronically," said Swartzwelder. "In terms of acute effects, a single heavy dose of alcohol will lead to a decrease in a person's executive functioning, particularly in terms of what we call 'working memory.' Working memory allows you to juggle several cognitive 'balls' at the same time, and remember what you've been doing. In terms of chronic alcohol consumption, the effects are much broader, and particularly damaging to the frontal lobes, that region of the brain that really is responsible for executive functioning. It occurred to us that, among people who have just stopped drinking, there may still be some residual effects from their acute consumption as well as cumulative effects from their chronic drinking."
All of the study participants were male veterans receiving treatment at the Durham Veterans Affairs Medical Center. Researchers administered memory and executive-function tests to two groups, alcohol-dependent participants (n=27) receiving treatment at an outpatient substance-abuse clinic, and age-matched primary-care outpatients (n=18). Researchers then compared the groups' neuropsychological performance, self-evaluation of cognitive status, and associations between drinking history and cognitive impairment.
Results indicate that the alcohol-dependent and non-dependent groups differed on abstract reasoning, memory discrimination, and effectiveness on timed tasks.
"These deficits may very well limit a person's ability to engage in effective planning and strategizing, both in terms of their treatment compliance and in terms of their everyday lives," said Swartzwelder. "This implies that, not only do the clinicians who are treating alcoholics have to take their executive dysfunction into account, but so do their spouses, children, bosses and other social contacts."
"Deficits in these cognitive abilities could render us debilitated," added Oscar-Berman. "Depending upon the nature and severity of the deficits, we might not be able to remember things from one moment to the next, which could interfere with our ability to learn anything new. Neither would we be able to solve problems nor plan our future actions."
Clinicians need to begin to actively develop therapies that capitalize on the functions that remain intact and minimize reliance on those functions that are compromised, said Swartzwelder.
"When we treat people for alcohol abuse or alcohol addiction, early in the treatment program - that is, shortly after they are first abstinent - we ask them to do a lot of cognitive things," he said. "In fact, most of the treatments used are cognitive or behavioral in nature, like psychotherapy, group therapy, 12-step programs, etc. But if a person has executive dysfunction, they are going to be compromised in terms of their ability to plan ahead, execute those plans, and stay with the program. It's like asking them to run with a bum leg."
"To optimize treatment," added Oscar-Berman, "it would be very important to help an alcoholic with executive dysfunction to develop mnemonic devices for treatment adherence, and for care givers to be persistent in helping the patient to not persevere with unhealthy behaviors (i.e. not to repeat the same mistakes over and over). However, it is important to keep in mind the cautionary note of the authors ... 'that the path from chronic drinking to real-world effects remains unclear, and more research is needed.' I think functional neuroimaging techniques provide the best methods for observing the component executive deficits in action, and to pinpoint the exact regions of the brain that are functioning abnormally."
Swartzwelder said the next important step is to determine how long the dysfunction lasts. "We also need to see if there's an age difference in terms of people's recovery of executive functioning after abstinence," he said. "One hypothesis is that there might be a different pattern of executive dysfunction among older folks during abstinence. On a related note, we really need to look at the implications of this research for adolescent alcoholics. Their executive functioning is not yet fully developed, and it might be that adolescent alcoholics in early abstinence may have an even different pattern of executive-function deficits."
Alcoholism: Clinical & Experimental Research (ACER) is the official journal of the Research Society on Alcoholism and the International Society for Biomedical Research on Alcoholism. Co-authors of the ACER paper, "Executive functioning early in abstinence from alcohol," were: Sandra Zinn of Research and Development, and Health Services Research and Development, at Durham Veterans Affairs Medical Center, as well as the Department of Psychiatry and Behavioral Sciences at Duke University Medical Center; and Roy Stein of the Department of Psychiatry and Behavioral Sciences at Duke University Medical Center, as well as Mental Health Services at Durham Veterans Affairs Medical Center. The study was funded by the U.S. Department of Veterans Affairs, Veterans Health Administration, Health Services, and the National Institute on Alcohol Abuse and Alcoholism.