Do children with attention-deficit/hyperactivity disorder (ADHD) have set shifting deficits?

Set shifting, or cognitive flexibility, is a core executive function involving the ability to quickly and efficiently shift back and forth between mental sets. Meta-analysis suggests medium-magnitude shifting impairments in attention-deficit/hyperactivity disorder (ADHD). However, this conclusion may be premature because the evidence-base relies exclusively on tasks that have been criticized for poor construct validity and may better reflect general neuropsychological functioning rather than shifting specifically.

A well-characterized sample of 77 children ages 8-13 (M = 10.46, SD = 1.54; 32 girls; 66% Caucasian/non-Hispanic) with ADHD (n = 43) and without ADHD (n = 34) completed the criterion global-local set shifting task and 2 counterbalanced control tasks that were identical in all aspects except the key processes.

The experimental manipulation was successful at evoking set shifting demands during the global-local versus both nonshift control tasks (p < .001; ω2 = .12-.14). Mixed-model analyses of variance (ANOVAs) revealed that the ADHD group did not demonstrate disproportional decrements in speed shift costs on the shifting versus nonshift control tasks (p = .30; ω2 = .002), suggesting no evidence of impaired set shifting abilities in ADHD. In contrast, the ADHD group made disproportionately more shifting errors than the non-ADHD group (p = .03; ω2 = 0.03) that were more parsimoniously attributable to prerequisite (nonshifting) processes necessary for successful performance on the global-local task.

Children with ADHD's impaired performance on shifting tasks may be attributable to difficulties maintaining competing rule sets and/or inhibiting currently active rule sets prior to shifting. However, when these higher-order processes are executed successfully, there is no significant evidence to suggest a unique set shifting deficit in ADHD. (PsycINFO Database Record (c) 2019 APA, all rights reserved).