05 January 2007

Impulsivity tied to drinking

A lack of impulse control may be a warning sign for an increased risk of alcoholism, a new study suggests.

A lack of impulse control may be a warning sign for an increased risk of alcoholism, a new study suggests.

The researchers said they substantiated their finding by showing reduced inhibitory activity in the frontal lobes of the brains of alcoholics.

The study, by scientists at the State University of New York Downstate Medical Centre, is published in the January issue of the journal Alcoholism: Clinical & Experimental Research.

"We have been finding that alcoholics have a low amplitude of a particular brain wave," said Bernice Porjesz, a professor and director of the Henri Begleiter Neurodynamics Laboratory at the centre. "We have also found it in their offspring, even though they have not had any exposure to alcohol," she added.

Impulsivity linked to various risks
Porjesz noted that, in children, signs of problems controlling impulses can signal a risk of substance abuse, behaviour and learning problems.

The brain signal in question is linked with the inability to inhibit matters that are irrelevant, and it appears to be present in people who become alcoholics, Porjesz explained. "It may make them more vulnerable to becoming an alcoholic," she said.

Porjesz also found that even non-alcoholics with impulsive behaviours have the reduced frontal lobe brain activity while doing tasks that require focusing and using the frontal lobes.

Although this condition is probably genetic, Porjesz is quick to note that poor impulse control is not a cause of alcoholism. "There is no alcoholism gene," she said.

How the study was conducted
In the study, Porjesz's group evaluated 57 alcoholics and compared them with 58 healthy adults. All those in the study were tested with a standard visual task, in which they had to press a button only when they saw rarely occurring target stimuli - in this case, the letter X, which was embedded in a series of other letters.

During the test, the researchers recorded brain waves, using 61 scalp electrodes to measure P3 amplitudes. P3 amplitudes reflect levels of neural inhibition in the central nervous system - the larger the P3, the more the inhibition. Porjesz's team also measured impulsiveness with a standard questionnaire filled out by the study participants.

The researchers found that the alcohol-dependent individuals, as well as people with high impulsivity, had significantly lower P3 amplitudes and reduced frontal-lobe activity during the visual target signals test.

Porjesz thinks this reduced frontal lobe activity is emblematic of other addictive behaviours. "We have been finding that this is associated with certain genes," she said. "We are looking at whether these genes are associated with increased risk. We see these same brain wave disorders in children who have attention deficit disorder and antisocial personality disorder."

Brain wave tied to risk
People who have this kind of brain wave signature are more at risk for alcoholism and addiction to other drugs, Porjesz said.

One expert thinks this study might lead to new ways to treat alcoholics with this particular brain wave pattern.

"This finding extends work that this group [of researchers] and others have been doing for many years," said Dr J.C. Garbutt, a professor of psychiatry at the University of North Carolina at Chapel Hill. "It is well known that the behavioural trait of impulsivity is a risk factor for alcoholism. It is also now established that the electrophysiological marker known as a reduced P3 is also a risk factor for alcoholism."

The importance of this new study is that it helps to build understanding of the behavioural and neurobiological characteristics associated with alcoholism, Garbutt said. "It is likely that not all alcoholics will have these characteristics, but a substantial number might. As we understand the underpinnings of alcoholism, we are better able to design prevention and treatment strategies," he said. – (HealthDayNews)

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