"Impulsivity is a central feature of drug addiction and may arise as a result of impaired inhibitory control. The extent to which inhibitory deficits arise as a consequence of drug exposure or relate to pre-existing addiction vulnerability is unknown," researchers in Cambridge, the United Kingdom report (see also Alcoholism).

"This study compared measures of impulsivity in outpatients with alcohol dependence (n = 23) and problem gambling (n = 21), a putative behavioural addiction where direct effects of drug exposure may be minimal. Healthy controls (n = 27) were also tested, in a cross-sectional design. completed the stop-signal test as a neurocognitive probe of response inhibition, alongside self-report ratings of impulsivity, adult ADHD and OCD. On the stop-signal test, Go reaction time and stop-signal reaction time were significantly slower in the alcohol-dependent group, compared with healthy controls. Healthy controls slowed their responding after successful and failed stop trials. Slowing after failed stop trials was significantly attenuated in the alcohol-dependent subjects. Go reaction time and post-error slowing were correlated with chronicity and severity, respectively, in the alcohol-dependent subjects. Problem gamblers did not differ significantly from controls on the stop-signal test, despite trait elevations in impulsivity ratings. Inhibitory control is impaired in alcohol dependence but occurs in the context of psychomotor slowing. In addition, alcohol-dependent individuals failed to show behavioral adjustment following failed stops," wrote A.J. Lawrence and colleagues, University of Cambridge.

The researchers concluded: "These deficits may represent direct effects of chronic alcohol administration on fronto-striatal circuitry."

Lawrence and colleagues published their study in Psychopharmacology (Impulsivity and response inhibition in alcohol dependence and problem gambling. Psychopharmacology, 2009;207(1):163-172).

For additional information, contact L. Clark, University of Cambridge, Dept. of Experimental Psychology, Behavioral & Clinic Neuroscience Institute, Downing St., Cambridge CB2 3EB, UK.

Publisher contact information for the journal Psychopharmacology is: Springer, 233 Spring St., New York, NY 10013, USA.