Attentional function and inhibitory control in different substance use disorders

Abstract

Attentional function in substance use disorder (SUD) is not well understood. To probe attentional function in SUD as a function of primary substance of abuse, we administered the attentional network task (ANT) to 44 individuals with Cocaine Use Disorder (CoUD), 49 individuals with Cannabis Use Disorder (CaUD), 86 individuals with Opioid Use Disorder (OUD), and 107 controls with no SUD, along with the stop-signal task (SST). The ANT quantifies the effects of (temporal) alerting cues and (spatial) orienting cues to reduce reaction time (RT) to targets, as well as probing how conflicting (target-incongruent) stimuli slow RT. The SST quantifies individuals' ability to inhibit already-initiated motor responses. After controlling for sex representation and age, OUD and CaUD participants showed blunted alerting effects compared to controls, whereas CaUD and CoUD participants showed greater stimulus conflict (flanker) effects. Finally, CoUD participants showed a trend toward increased orienting ability. In SST performance, no SUD group showed a prolonged stop-signal reaction compared to controls. However, the OUD group (and CoUD group at trend level) showed prolonged "go" RT to targets and reduced hit rates. These data indicate differences in attentional function in persons with SUD as a function of the primary substance use.

Keywords: Attention; Cannabis; Cocaine; Executive function; Impulsivity; Opioids; Substance use disorder.

Figure 1.

Diagram of Attentional Network Task. In each trial of the Attentional Network Task (ANT), the participant must report the direction of the center arrow of an array of arrows with the corresponding mouse button (L or R) within a 1700 ms window. Trials began on average 4 s apart, and were separated by a variable intertrial interval (ITI). The top screen sequence illustrates a “no-cue” trial, in where there is no spatial or temporal warning cue prior to the arrow target presentation. In this example, the flanking arrows are congruent with the central, left-pointing target arrow. The middle screen sequence illustrates an “alerting” cue trial in which a centrally-located row of asterisks replaces the fixation cross for 100 ms, 500 ms prior to the target. In this example, the flanking arrows are incongruent with the target arrow, and point in the opposite direction. The bottom screen sequence illustrates an “orienting” cue trial, wherein a row of asterisks appears 500 ms prior to the target in the precise location of the forthcoming target. In this example, the arrow target itself is congruous, because the flanking arrows point the same direction as the central arrow target.

Figure 2.

Main effects of ANT trial conditions. Shown here are the accuracy rates (reporting proper direction of target arrow within the time window) (Panel A) and outlier-trimmed mean reaction times (RT) to trial targets (Panel B) as a function of whether the trial featured an advance warning cue (alerting or orienting) and whether the target arrow was congruous or incongruous with the direction of the flanking arrows. For both accuracy and for mean RT values, there were significant main effects of cue type and target congruency, as well as cue type X congruency interaction effects.

Figure 3.

Shown here are adjusted mean values for each of the ANT alerting effect (Panel A), orienting effect (Panel B) and Executive/conflict effect (Panel C), after inclusion of age, sex, and their interactions with group in the regression model. Error bars represent 95% confidence intervals. Horizontal brackets denote significant difference at p < .05.