Californians with multiple DUI convictions have subtle deficits in their decision-making abilities which are not necessarily detected through conventional tests.
Thirty four male, second DUI offenders enrolled in a rehabilitation program and a research control group of thirty one healthy, non-offenders matched for age, education, and alcohol use.
Each participant had psychiatric assessments and conventional neuropsychological testing, including the the Iowa Gambling Task (IGT), to help assess personality patterns. IGT is used in many studies investigating alcohol problems because it simulates real-life decision-making.
"We found that second-time DUI offenders have a poorer performance on the IGT test than their matched counterparts," Muzaffer Kasar, a resident in psychiatry at the Bakirkoy Research and Training Hospital in Istanbul, Turkey, said in a journal news release.
In contrast, he and colleague David J. Nutt, a professor of psychiatry at Imperial College London in the U.K., found no differences between the repeat DUI offenders and the control group on conventional neuropsychological testing and temperament and character testing (TCI) scores.
"These findings suggest that second-time DUI offenders do not suffer from motor impulsiveness -- that is, a lack of impulse control in 'here and now' situations," Nutt said. Instead, he explained, "they suffer from cognitive impulsiveness, which depends on associating negative experiences with possible negative consequences."
In other words, "there are brain reasons for why people make poor choices regarding DUI," he added.
The researchers urged that such testing be expanded for people convicted of DUI, which they noted accounted for 40 percent of the fatal motor vehicle crashes in the United States. In addition, they said, 33 percent of the DUI drivers were recidivists, or repeat offenders.
The study appears online and in the December print issue of the journal Alcoholism: Clinical & Experimental Research.