A consistent attentional bias for drug-related material in active cocaine users across word and picture versions of the emotional Stroop task
Introduction
Previous research with emotional Stroop tasks have demonstrated an attentional bias for drug-related stimuli in abusers of alcohol (Cox et al., 2003, Duka and Townshend, 2004, Lusher et al., 2004) nicotine (Waters et al., 2003, Wertz and Sayette, 2001) and heroin (Franken et al., 2000b, Franken, 2003). These data have been interpreted as reflecting a preoccupation with drug-related stimuli caused by drug use. For example, when participants are pre-occupied with alcohol they take significantly longer to respond (verbally or motorically) with the colour of a word such as beer, than a neutral word such as table (Lusher et al., 2004). These studies provide support for the hypothesis that part of the addiction process is an alteration in attentional processing (Lyvers, 2000, Robinson and Berridge, 2003), whereby substance-related cues attain greater salience, particularly during craving for the drug (Cox et al., 2002).
While studies with active cocaine users have indicated a strong physical reaction to drug-related stimuli (Carter and Tiffany, 1999, Childress et al., 1993, Robbins et al., 2000), including activity in the limbic-based neural reward network that responds to the drug itself (Grant et al., 1996, London et al., 1999, Reid et al., 2003), research examining an attentional bias for cocaine-related stimuli has been limited (Franken et al., 2000a, Rosse et al., 1997). A recent study of patients with: (1) diagnosis of cocaine dependence; (2) schizophrenia; (3) schizophrenia and a comorbid diagnosis of cocaine dependence, administered a modified version of an emotional Stroop task (a task in which participants must respond to the font colour of emotionally charged words including cocaine-related words), and found that only cocaine-dependent patients demonstrated an attentional bias for cocaine-related stimuli (Copersino et al., 2004). A number of methodological considerations limit the generalisability of these results, including the inpatient status of cocaine users, medication regimes for some patients (including in the cocaine dependent group), the significant demographic (age and education) differences between the control and cocaine-dependent groups, and the task administration that utilized a card system requiring self-correction of errors (RT scores using this method can be influenced by a preponderency to inhibitory errors, which both cocaine users and schizophrenics are consistently shown to exhibit). Despite these limitations, the study was also able to demonstrate a relationship between an attentional bias for cocaine-related stimuli and self-reported craving for cocaine in the cocaine-dependent group, suggesting a wider clinical utility for such attentional measures.
Examining the salience of drug-related cues to attention is of interest for dual reasons. First, recent theories on the underlying neurobiological basis of drug addiction argue that the reactivity of neural reward circuits to drug-related cues represents an ‘overvaluation’ of drug reinforcers (Goldstein and Volkow, 2002). They propose that attention to drug-cues results from, and further reinforces, their salience because the activation of reward circuits appears to increase expectancy (and therefore craving) of the drug of abuse. Understanding the mechanism by which attention is captured by salient drug-related stimuli would appear critical to our understanding of craving and the addiction process (Robinson and Berridge, 2003). The mechanism underlying drug-related attentional bias might offer a potential target for treatment because of the association between drug craving and likelihood of relapse during withdrawal (Bordnick and Schmitz, 1998, Ciccocioppo et al., 2001, Weiss et al., 2001).
Second, studies with alcohol-abuse participants indicate that monitoring attentional bias to alcohol-related stimuli can predict drug-seeking behaviour (Cox et al., 1999, Cox et al., 2003), and more importantly predict those individuals most at risk of relapse during withdrawal (Cox et al., 2002). Also, studies with smokers show that attentional bias has a predictive value for smokng cessation (Waters et al., 2003). These findings suggest that measuring attentional ‘pre-occupation’ with drug-related stimuli may have a clinical utility that has yet to be fully explored. The concept of monitoring cue-reactivity and relating it to cocaine seeking behaviour has been attempted previously with these studies primarily using physiological measures of cue-reactivity such as skin-conductance, blood pressure and heart rate (Childress et al., 1993). To date, this approach has been unable to demonstrate a relationship with either drug-use behaviour (Robbins et al., 2000) or treatment outcome (Margolin et al., 1994), though this research is continuing. A reliable cognitive measure of attentional bias in cocaine users, capable of predicting treatment outcome, would be a useful tool for clinicians, particularly one which was short and easy to administer.
The aim of the current study was to modify the computer administered version of the emotional Stroop paradigm for examining attentional biases in active cocaine users. Given the robust effect sizes previously identified with the alcohol-related emotional Stroop, it was hoped that this paradigm would provide a more sensitive measure than previous attempts at measuring attentional bias in cocaine users (Copersino et al., 2004, Franken et al., 2000a). Self-report measures of drug use were also obtained to ascertain whether attentional biases could be related to drug-use behaviour patterns such as length (years of drug-use), or frequency (number of uses per week, money spent per week, etc.) of use.
An additional aim of the current study was to compare word and picture versions of a cocaine version of the emotional Stroop task. The typical paradigm design for emotional Stroop tasks presents drug-related words in varying font colours, which the participant must respond to by providing the font colour. Given the argument that increased latencies for drug-related words are the result of extra-time taken to process the semantic properties of the stimulus (Lusher et al., 2004), we administered both a typical word-based emotional Stroop paradigm and a modified picture-based version. The latter task presented black and white pictures of cocaine-related, non-drug-related evocative, and neutral material within coloured borders. The participant's task was to press a button that corresponded with the colour of the picture border. We hypothesized that pictures, when compared to words, might have more salience for users, because previous research has suggested that cue-reactivity of cocaine-users does vary as a function of cue-type and modality (Johnson et al., 1998), and previous work with an eating-disorder version of the emotional Stroop task suggests greater effects for pictures when compared to words (Stormark and Torkildsen, 2004).
Section snippets
Participants
Twenty-three non-drug using participants (seven female, mean age 39.4, range 26–51) and 23 active cocaine users (seven female, mean age 40.3, range 22–48) participated in the current study. Educational attainment for the two groups was not significantly different (controls: 12.4 years, users: 11.8, F(1, 44) = 3.09, p > 0.05). All participants were right-handed and reported no current or past history of neurological or psychiatric disorders, dependence on any psychoactive substance other than
Word emotional Stroop task
Accuracy performance for both users and controls was close to ceiling (over 95% for all word categories), and did not indicate any group or categorical influences. Inspection of the reaction time data revealed one cocaine-user participant was a significant outlier for RT measures from both versions of the task, being greater than three standard deviations higher than the mean for several of the measures derived, and was omitted from the subsequent analyses. The mean RT and standard deviation
Discussion
The results of the current study indicate that active cocaine users demonstrate a significant attentional bias for cocaine-related stimuli, consistent across both word and picture versions of the emotional Stroop task. Our analyses also suggest that the attentional bias could not be attributed to confounding factors such as slowed response speed of cocaine users, cocaine-related material sharing category ownership, or that the cocaine-related material used in the current study was generally
Acknowledgements
This research was supported by USPHS grant DA14100 and GCRC M01 RR00058. The assistance of Stacy Claesges is gratefully acknowledged.
References (38)
- et al.
Reduced cerebral blood flow in anterior cingulate cortex (ACC) during Stroop performance in chronic cocaine users
Hum. Brain Mapp.
(2001) - et al.
Cocaine craving: an evaluation across treatment phases
J. Subst. Abuse
(1998) - et al.
Cocaine craving and attentional bias in cocaine-dependent schizophrenic patients
Psychiatry Res.
(2004) - et al.
Alcohol attentional bias as a predictor of alcohol abusers’ treatment outcome
Drug Alcohol Depend.
(2002) - et al.
Effects of alcohol cues on cognitive processing in heavy and light drinkers
Drug Alcohol Depend.
(1999) - et al.
Acute and residual effects of marijuana in humans
Pharmacol. Biochem. Behav.
(1998) Drug craving and addiction: integrating psychological and neuropsychopharmacological approaches
Prog. Neuropsychopharmacol. Biol. Psychiatry
(2003)- et al.
Influence of individual differences in craving and obsessive cocaine thoughts on attentional processes in cocaine abuse patients
Addict. Behav.
(2000) - et al.
Cue reactivity in cocaine-dependent subjects: effects of cue type and cue modality
Addict. Behav.
(1998) - et al.
Incubation of cocaine craving after withdrawal: a review of preclinical data
Neuropharmacology
(2004)
Alcohol dependence and the alcohol Stroop paradigm: evidence and issues
Drug Alcohol Depend.
Cue-elicited cocaine craving and autogenic relaxation. Association with treatment outcome
J. Subst. Abuse Treat.
Mood state and recent cocaine use are not associated with levels of cocaine cue reactivity
Drug Alcohol Depend.
Selective processing of linguistic and pictorial food stimuli in females with anorexia and bulimia nervosa
Eating Behav.
Meta-analysis of cue-reactivity in addiction research
Addiction
Cue reactivity and cue reactivity interventions in drug dependence
NIDA Res. Monogr.
Cocaine-predictive stimulus induces drug-seeking behavior and neural activation in limbic brain regions after multiple months of abstinence: reversal by D(1) antagonists
Proc. Natl. Acad. Sci. USA
The effects of alcohol cue exposure on non-dependent drinkers’ attentional bias for alcohol-related stimuli
Alcohol Alcohol.
Cited by (152)
Negative Urgency Exacerbates Relapse to Cocaine Seeking After Abstinence
2022, Biological PsychiatryOver-representation of fundamental decision variables in the prefrontal cortex underlies decision bias
2021, Neuroscience ResearchMotivated perception for self-regulation: How visual experience serves and is served by goals
2021, Advances in Experimental Social PsychologyFrom sign-tracking to attentional bias: Implications for gambling and substance use disorders
2020, Progress in Neuro-Psychopharmacology and Biological Psychiatry