Stop What You're Doing!—An fMRI Study on Comparisons of Neural Subprocesses of Response Inhibition in ADHD and Alcohol Use Disorder

Abstract

Rationale: Both attention deficit-/hyperactivity disorder (ADHD) and alcohol use disorder (AUD) are accompanied by deficits in response inhibition. Furthermore, the prevalence of comorbidity of ADHD and AUD is high. However, there is a lack of research on whether the same neuronal subprocesses of inhibition (i.e., interference inhibition, action withholding and action cancellation) exhibit deficits in both psychiatric disorders.Methods: We examined these three neural subprocesses of response inhibition in patient groups and healthy controls: non-medicated individuals with ADHD (ADHD; N = 16), recently detoxified and abstinent individuals with alcohol use disorder (AUD; N = 15), and healthy controls (HC; N = 15). A hybrid response inhibition task covering interference inhibition, action withholding, and action cancellation was applied using a 3T functional magnetic resonance imaging (fMRI).Results: Individuals with ADHD showed an overall stronger hypoactivation in attention related brain areas compared to AUD or HC during action withholding. Further, this hypoactivation was more accentuated during action cancellation. Individuals with AUD recruited a broader network, including the striatum, compared to HC during action withholding. During action cancellation, however, they showed hypoactivation in motor regions. Additionally, specific neural activation profiles regarding group and subprocess became apparent.Conclusions: Even though deficits in response inhibition are related to both ADHD and AUD, neural activation and recruited networks during response inhibition differ regarding both neuronal subprocesses and examined groups. While a replication of this study is needed in a larger sample, the results suggest that tasks have to be carefully selected when examining neural activation patterns of response inhibition either in research on various psychiatric disorders or transdiagnostic questions.

Neural underpinnings of response inhibition in substance use disorders: weak meta-analytic evidence for a widely used construct

“…We did not suspect any overlap between the studies because the studies with the same authors differed in terms of the sample studied, the collection parameters, the study design, and the demographic characteristics. The study by Gerhardt et al ( 2021 ) investigated both GNGT and SST paradigm in the same sample. We have treated these data as a single experiment because splitting the experiments into two different ones would suggest statistical independence, which we argue is not given by using the same sample.…”

“…Furthermore, in this study we suspected errors in 2 peak coordinates that were outside the mask when first checked or incongruent with the brain location declared. The first coordinate ( x = − 38, y = 72, z = 44) should indicate a peak in the inferior parietal lobule, whereas this is located far outside the mask (Gerhardt et al 2021 ). The sign of the y -coordinate seems to be incorrect, so that we assume, in line with the reported brain area, that the coordinate should have been x = 38, y = − 72, z = 44.…”

Drinking alcohol to cope with hyperactive ADHD? Self-reports vs. continuous performance test in patients with ADHD and/or alcohol use disorder

“…In ADHD, new and interesting situations with low distraction – as in (laboratory) research – often lead to a temporary decrease in symptoms including hyperactivity ( 37 ). Functional imaging studies on AUD and ADHD showed similar impulsivity and resting state brain networks ( 38 ), but brain activation during inhibition tasks depended on ADHD and AUD severity ( 39 ). These findings, together with our results, suggest that in ADHD a less effective brain network compensates impulsivity, which might be more vulnerable to distractors or a general increased level of stress in real life ( 40 ), but not in a controlled laboratory setting.…”

Methylphenidate as a treatment option for substance use disorder: a transdiagnostic perspective

“…To the best of our knowledge, there is one study comparing ADHD and SUD directly on objective measures of inhibitory control. Gerhardt et al (78) observed more commission errors in ADHD subjects compared with alcohol use disorder subjects in a comprehensive paradigm assessing various cognitive aspects of impulsivity. However, they did not observe any behavioral differences on six other measures.…”

“…One study directly compared brain activation of ADHD and alcohol use disorder patients as elicited by a comprehensive response inhibition task (78). Authors report more activation of a frontoparietal network, cortical and subcortical motor areas, and occipital areas in alcohol use disorder patients compared with ADHD patients.…”