Prepotent response inhibition in autism: Not an inhibitory deficit?

Research outcomes on prepotent response inhibition in neurodevelopmental conditions during adulthood seem inconsistent, especially in autism. To gain further insight in these inconsistencies, the current study investigates inhibitory performance, as well as task strategies such as adaptive behavior during inhibitory tasks in autistic adults. As Attention-Deficit/Hyperactivity Disorder (ADHD) is often co-occurring in autism and associated with differences in both inhibition and adaptation, the role of ADHD symptoms is explored. Additionally, prior research is extended to middle- and late-adulthood, and the role of cognitive aging is assessed. Hundred-and-five autistic adults and 139 non-autistic adults (age: 20-80 yrs) were compared on a Go-NoGo task. No significant group differences in inhibitory difficulties (commission errors) or adaptation (post error slowing) were observed, and both did not relate significantly to ADHD symptoms. However, when controlling for reaction time autistic individuals made significantly more inhibitory errors than non-autistic individuals, yet the effect size was modest (Cohen's d = .27). Exploratory analyses showed that adaption significantly related to inhibition in non-autistic individuals only, possibly hinting at altered adaptive behavior during inhibitory tasks in autistic adults. ADHD symptoms related to response variability in the autism group only. Furthermore, task strategy changed with older age in both groups, with slower and more cautious responses at older age. Taken together, although minor differences may exist, autistic and non-autistic people show largely similar patterns of inhibitory behavior throughout adulthood. Differences in task timing and strategy seem relevant for future longitudinal studies on cognitive aging across neurodevelopmental conditions.