Studies using the colour–word Stroop task in addicted individuals report results that mostly echo those reported above. For example, cocaine abusers had lower CBF in the left dACC and right DLPFC during incongruent trials compared to congruent trials, whereas the right ACC showed the opposite pattern; moreover, right ACC activation was negatively correlated with cocaine use121 (Supplementary information S6 (table)). In marijuana-using men, lower CBF during this task was reported in several PFC regions, including perigenual ACC, ventromedial PFC and DLPFC122. Methamphetamine-dependent subjects also showed hypoactivations in the inhibitory control network, including dACC and DLPFC while performing this task123. Consistent with the impact of abstinence on the go/no-go task reported above114, cigarette smokers who were tested after a 12-hour abstinence had slowed reaction times, and enhanced dACC and reduced right DLPFC responses to the incongruent trials on the colour–word Stroop task124 (Supplementary information S4(table)). Importantly, an fMRI study showed that activation of the ventromedial PFC (Brodmann areas 10 and 32) during a colour–word Stroop task performed 8 weeks before treatment onset predicted treatment outcome in cocaine-addicted individuals125.
