Results are published in the November issue of Alcoholism: Clinical & Experimental Research.
"Around 50 percent of alcoholic patients have psychiatric disorders that include pathological impulsivity," said Gabriel Rubio, associate professor at Complutense University of Madrid, Spain. Yet few studies have explored behavioral measures of impulsivity within different alcoholic subpopulations, which could have important treatment and relapse implications.
Cluster B personality disorders involve dramatic or erratic behaviour. "The two most frequent cluster B personality disorders found in alcoholic samples are borderline personality and antisocial personality disorders," said Rubio. "We did not know if impulsivity found in alcoholics is due to a specific trait typical of alcoholism or is due to comorbidity with cluster B personality disorders." Accordingly, they designed their study to assess if alcoholic patients with borderline personality disorder exhibited the same pattern of behavioral impulsivity as alcoholic patients with antisocial personality disorder.
Rubio and his colleagues examined two groups: 247alcoholic men recruited from two alcohol-treatment centers, and 96 non-substance-abusing men from the community that were matched on age and education. The researchers measured inhibitory control, and assessed sustained attention, rapid-response impulsivity, and ability to delay reward, for all participants.
"Our results indicated that alcoholics without cluster B personality disorders displayed a greater inability to delay gratification than control healthy subjects," said Rubio. "This means that a subject prefers a smaller but sooner expected value, such as a drink right now, over a later but larger expected value, such as increases in health or psychological condition. We can hypothesize that this subject will relapse very quickly."
The second finding involved alcoholics with cluster B personality disorders, who displayed more impairment on inhibitory control. "This means that a subject has problems with appropriately inhibiting thoughts or actions," said Rubio. "In other words, when an action has begun, such as drinking that first drink, he or she will have difficulties stopping, meaning he or she cannot stop drinking."
Rubio said these finding suggest that the traditional perception of alcoholism and impulsive behaviour may need to be reconsidered. "High levels of behavioural impulsivity may be related to other disorders, such as borderline personality or antisocial personality disorders, which are frequently present in subsets of alcoholics," he said. "We may also need to rethink treatment options. Programs that emphasize immediate rewards for abstinence may have a better chance of succeeding with antisocial personality disorder. Conversely, psychotherapeutic and pharmacological interventions that focus on 'behavioral control' may work better with subjects with borderline personality disorders."