Impulsivity and response inhibition in alcohol dependence and problem gambling

Abstract

Introduction 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. Materials and methods 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. Subjects completed the stop-signal test as a neurocognitive probe of response inhibition, alongside self-report ratings of impulsivity, adult ADHD and OCD. Results On the stop-signal test, Go reaction time and stopsignal 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 alcoholdependent subjects. Problem gamblers did not differ significantly from controls on the stop-signal test, despite trait elevations in impulsivity ratings. Conclusion 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. These deficits may represent direct effects of chronic alcohol administration on fronto-striatal circuitry.

Stress and Alcohol Cues Exert Conjoint Effects on Go and Stop Signal Responding in Male Problem Drinkers

“…ADS also correlated with trait Impulsivity, which is consistent with the well-established relationship between alcohol dependence and impulsivity (Finn, 2002;Limosin et al, 2003;Schuckit, 2009;von Diemen et al, 2008), and thus strengthens the external validity of the present data. The relatively stronger (inverse) correlation between SSRT to Alcohol words and ADS suggests that the severity of the dependence syndromeFa dynamic variableFbetter predicts the debilitating effect of salient stimuli on inhibitory control than does a stable trait like Impulsivity, although alcohol dependence per se may also involve global inhibitory deficits on the SST (Lawrence et al, 2009).…”

“…However, the conditions that are necessary for these effects remain to be determined. Important variables that may well moderate the Go and Stop processes include addiction status and gender, both of which have been found to affect responses to stress and cues on other cognitive indices (Chaplin et al, 2008;Fox et al, 2009;Lawrence et al, 2009;Li et al, 2009;Nesic and Duka, 2006;Udo et al, 2009). In addition, the present subjects were active drinkers and may therefore differ from individuals who have undergone treatment.…”

“…In addition, the present subjects were active drinkers and may therefore differ from individuals who have undergone treatment. Trial-by-trial topography of RT has also been linked with anomalies in neural function in alcohol-dependent subjects (Lawrence et al, 2009;Li et al, 2009). Coding trials to capture these temporal variations could reveal additional effects of salient stimuli.…”

“…The GNG and SST discriminate between addicted individuals and controls, suggesting that these tasks may operationalize key addiction-related inhibitory deficits (Kamarajan et al, 2005;Lawrence et al, 2009). However, inhibitory performance is also sensitive to situational factors.…”

Evidence for GABA‐A receptor dysregulation in gambling disorder: correlation with impulsivity

“…A major feature common to gambling and substance‐related disorders is impaired impulse control, which may be fundamental to both the development and maintenance of addictive disorders (Bechara 2005; Lawrence et al 2009; Verdejo‐Garcia et al 2008). We have previously shown that Negative Urgency (NU) derived from the UPPS‐P impulsivity scale is related to dopamine D2/3 receptor availability in GD (Clark et al 2012) and also to MOR availability (Mick et al 2015).…”