I found a study from 2007 (Rommelse et al., 2007) that found no differences between ADHD and control groups in cognitive flexibility, but a few more recent ones that indeed found a difference (Xiang Zhang et al., 2023 / Roshani et al., 2020 / Kercood et al., 2017 / Wixted et al., 2016). However, the old study from 2007 had a bigger sample size than the other studies. I also found a study that showed underactivity in brain regions associated with cognitive flexibility in people with ADHD (Sára Bálint et al., 2015).

What is the recent scientific literature about ADHD and cognitive flexibility? Is there a meta-analysis? Do people with ADHD indeed experience deficits in cognitive flexibility?