The goal of the current study was to tailor a classical NP tool, verbal fluency, to possibly improve its sensitivity and ecological validity in an effort to advance research on addictive disorders. Indeed, compared to age- and education-matched control subjects, the cocaine subjects that tested positive for cocaine at study day named more drug-related words on this modified drug fluency task. . Compared to the control subjects, both cocaine subgroups (with positive or negative urines for cocaine at study day) also provided more drug-related words that were from goal-directed categories (e.g., smoking the drug and instruments implemented to use drugs). In contrast, the control subjects provided more non-addictive drug names.
Overall, we interpret these findings to indicate greater attentional bias and responsivity to drug-related cues in individuals with cocaine use disorders similarly to that previously reported in abusers of alcohol (Duka and Townshend, 2004
), nicotine (Mogg and Bradley, 2002
), heroin (Franken et al., 2000
), and cocaine (Hester et al., 2006
; Carpenter et al., 2006
) using the drug Stroop NP task. Note that although in our study there were no significant correlations between the current drug fluency task and drug use history, drug fluency output was highest in the cocaine subgroup that tested positive for cocaine at study day; these results are therefore consistent with prior results showing that a similar automatic processing bias is related to cocaine craving (Copersino et al., 2004
; Hester et al., 2006
) and may also be predictive of treatment outcome (Cox et al., 2002
Our current drug fluency task may have also tapped heightened (“fresher”) memory for drug-related stimuli in the individuals with cocaine use disorders (Lee et al., 2006
). An additional differential NP process that may have been triggered by this task encompasses a compromised emotion regulation/suppression in a drug-related context in the individuals with cocaine use disorders as possibly modulated by the rostroventromedial prefrontal cortex (Goldstein, 2007
, in press). Nevertheless, the precise cognitive processes and neural circuits that underlie performance on this newly tailored task remain to be established .
Limitations of the current study include the following: (1) fixed order of administration of both the semantic and drug fluency tasks across all subjects (the drug fluency task always followed the semantic fluency tasks): a randomized order may have elicited somewhat differential responses from the study participants; (2) the reliability and reproducibility of this newly developed instrument remains to be tested in larger sample sizes and different drug use populations. It would be of particular interest to include a sample of healthy control individuals with a high familiarity of drug-related stimuli (e.g., family members of addicted individuals, staff in drug treatment facilities or other professionals in the drug addiction field) to further examine this task's specificity and predictive value. One could postulate that only in the drug addicted individuals, but not those highly familiar with drug addiction, responses on the drug fluency task would be diagnostically and clinically useful; (3) the use of this drug fluency task together with other measures of cognition (e.g., attention bias/cue reactivity, memory) and emotion (e.g., regulation), especially inside functional neuroimaging environments, is needed to ascertain the exact neurocognitive processes evoked by this task in drug addiction and other psychopathology; and (4) the contribution to results of craving, other withdrawal symptoms, and severity of use needs to be explored with more sensitive tools (e.g., other tasks that actively elicit craving), in as much as these factors have been associated with greater cue-reactivity in drug addicted individuals (e.g., (Childress et al., 1987