P300 Event-Related Potential Amplitude and Impulsivity in Cocaine-Dependent Subjects

Abstract

Previous studies report reduced amplitude of the P300 event-related potential in cocaine-dependent individuals. Cocaine dependence is also associated with increased impulsivity, possibly due to deficits in cognitive function that are associated with reduced P300 amplitude. In the current study, the relationship between cocaine dependence, impulsivity, and P300 amplitude were examined. An auditory oddball event-related potential task along with self-report (Barratt Impulsiveness Scale version 11) and behavioral laboratory (Immediate and Delayed Memory Task) measures of impulsivity were assessed in healthy controls (n = 14) and subjects who met DSM-IV criteria for current cocaine dependence (n = 17). P300 amplitude was reduced and self-reported and behavioral laboratory impulsivity scores were elevated among the cocaine-dependent group compared to controls. There was a positive correlation between the questionnaire and behavioral laboratory measures of impulsivity, and a negative correlation between impulsivity measures and P300 amplitude. The correlation between self-reported impulsivity scores and P300 amplitude remained after taking into account the number of childhood conduct disorder symptoms. This study supports the hypothesis that the basic neurophysiology responsible for the P300 amplitude in cocaine-dependent individuals is associated with impulsivity independent of a history of childhood conduct disorder symptoms.

Attentional deficits in cocaine-dependent patients: Converging behavioral and electrophysiological evidence

“…Studies of ERPs in cocaine dependent patients reveal reduced frontal P300 amplitude (Bauer, 1996;Bauer, 1997;Biggins et al, 1997;Bauer,2001). In a classic 'oddball paradigm', Moeller et al (2004) observed that the cocaine-dependent patients displayed significantly smaller P300 amplitudes than the controls. Moeller et al (2004) found a significant inverse relationship between P300 amplitude and years of cocaine use, as well as an inverse relationship between the patients' impulsivity measures and their P300 amplitude.…”

“…Using a co-twin control research design, Toomey et al (2003) observed that in their sample of 50 twin pairs discordant for abuse of cocaine and/or amphetamines , the drug-abusing co-twin displayed significantly better performance on the CPT, though impaired performance on other attentional measures. On the other hand, two more recent investigations (Moeller et al, 2004;Moeller et al, 2005) suggest that cocaine dependence may be associated with attentional impairments. In a comparison of 17 individuals with current cocaine-dependence and 14 controls, the cocaine-dependent subjects had significantly higher behavioral laboratory scores of impulsivity, operationally defined as proportion of hit-corrected false alarms, than controls (Moeller et al, 2004).…”

“…On the other hand, two more recent investigations (Moeller et al, 2004;Moeller et al, 2005) suggest that cocaine dependence may be associated with attentional impairments. In a comparison of 17 individuals with current cocaine-dependence and 14 controls, the cocaine-dependent subjects had significantly higher behavioral laboratory scores of impulsivity, operationally defined as proportion of hit-corrected false alarms, than controls (Moeller et al, 2004). In a later study (Moeller et al, 2005) 18 cocaine-dependent patients and 18 normal controls in were administered a questionnaire measure of impulsivity, namely, the Barratt Impulsivity Scale-11 (BIS-11), and the Immediate and Delayed Memory Task, and underwent diffusion tensor imaging (DTI).…”

“…The development of a cocaine-induced chronic psychosis is rare (Thirthalli & Benegal, 2006), relative to that of cannabis-and amphetamineinduced psychoses. We wanted to replicate the findings of Moeller et al (2004), namely, an association between P300 amplitude and a behavioral measure using a different subgroup of cocaine-dependent patients. We attempted to overcome some limitations of previous studies by using a well-validated measure of sustained attention, namely, the Continuous Performance Test-Identical Pairs Version (CPT-IP), assessing subjects for a childhood history of ADHD, obtaining an objective verification of abstinence from drug use, and including a normal control group.…”

“…The ln β value reflects the participant's response bias, with higher values indicating a more conservative response criterion. In order to allow comparisons with prior work by Moeller et al (2004), we also calculated an impulsivity index for each of the task conditions. The impulsivity index, intended to provide a more accurate rate of impulsive errors, was calculated by dividing the false alarm rate by the rate of correct detections.…”