Assessing Inhibitory Control Deficits in Adult ADHD: A Systematic Review and Meta-analysis of the Stop-signal Task

In recent years, there has been an increasing quest in improv i n g our understanding of the neurocognitive deficits underly i n g adult attention-deficit/hyperactivity disorder (ADHD). Current statistical manuals of psychiatric disorders emphasize inattention and hyperactivity-impulsivity symptoms, but empirical studies have also shown consistent alterations in inhibitory control. To date, there is no established neuropsychological test to assess inhibitory control deficits in adult ADHD. A common paradigm for assessing response inhibition is the stop-signal task (SST). Following PRISMA-selection criteria, our systematic review and meta-analysis integrated the findings of 26 publications with 27 studies examining the SST in adult ADHD. The meta-analysis, which included 883 patients with adult ADH D and 916 control participants, revealed reliable inhibitory con-trol deficits, as expressed in prolonged SST response times, with a moderate effect size g = 0.51 (95% CI: 0.376-0.644,p < 0.0001). The deficits were not moderated by study quality, sample characteristics or clinical parameters, suggesting that t h e y may be a phenotype in this disorder. The analyses of secondary outcome measures revealed greater SST omission errors and reduced go accuracy in patients, indicative of altered sustained attention. However, only few (N< 10) studies were available for these measures. Our meta-analysis suggests that the SST, in conjunction with other tests and questionnaires, could become a valuable tool for assessing inhibitory control deficits i n adult ADHD.

Automated summary

In recent years, there has been an increasing focus on understanding the neurocognitive deficits in adult ADHD. A meta-analysis of 26 publications with 27 studies found reliable inhibitory control deficits in adult ADHD patients, as demonstrated by prolonged SST response times. The results suggest that the SST, along with other tests and questionnaires, could be a valuable tool for assessing inhibitory control deficits in adult ADHD.