Decision-malting deficits, linked to a dysfunctional ventromedial prefrontal cortex, revealed in alcohol and stimulant abusers

A decision-making instrument known as the 'gambling task' was used, which h as been shown to be sensitive to the decision-making impairment of patients with bilateral lesions of the ventromedial prefrontal cortex (VM). Three g roups of subjects were tested, substance dependent individuals (SD) (n = 41 ), normal controls (n = 40), and VM patients (n = 5). All SD met the DSM-IV criteria for dependence, with either alcohol or stimulants (metamphetamine or cocaine) as the primary substance of choice. The results revealed a sig nificant impairment in the performance of SD relative to normal controls. A significantly high proportion of SD (61 vs. only 32.5% of normal controls) performed within the range of the VM patients, while the rest performed wi thin the range of normal controls. General demographic Factors such as age, sex, and level of education could not explain these differences in perform ance. As well, differences in performance were not explained by intelligenc e (IQ), memory, or performance on standard executive function/frontal lobe tests. Performance on the gambling task was best predicted by a combination of factors; including duration of abstinence, years of abuse, relapses and limes in treatment, and the ability to hold gainful employment. The result s support the hypothesis that impairment in decision-making linked to a dys functional VM cortex is associated with at least a sub-group of SD. (C) 200 1 Elsevier Science Ltd. All rights reserved.