Do people with ADHD show more trigger failures in response inhibition linked to increased mind wandering, as laboratory findings suggest?

What a trigger failure actually is

In a typical stopping experiment, a person is doing something fast, like pressing a button whenever a signal appears, and occasionally a stop signal tells them to cancel the movement they have already started. Stopping has two parts: first the brain must notice the stop signal and launch the brake, then it must carry the brake through. A trigger failure is when the first part does not happen at all, so the movement goes ahead as if no stop signal had arrived.

In healthy adults, mind wandering made stopping slower, and about two-thirds of the extra stopping time was explained by more trigger failures rather than by a weaker brake once it was engaged [1]. That is a clean, quantitative link: drifting attention seems to interfere mainly with noticing and launching the stop, not with the stopping machinery itself. The catch is that this was measured in healthy adults, not in people with ADHD [1].

ADHD does show altered inhibition, but not the same measurement

Children with ADHD do differ from typically developing children on laboratory inhibition tasks, but the pattern is not one uniform deficit. In a study of 300 children, girls with ADHD showed intact response inhibition while responding more slowly, whereas boys made more inhibition errors without slowing down; both groups showed higher response variability and poorer interference control [2]. That suggests the inhibition story in ADHD depends on sex and on which measure you look at, not simply on a global brake failure.

A separate study of children with ADHD using a conflict task found they committed more fast errors than control children, which the authors interpret as a stronger tendency to activate impulsive actions [5]. Again, this is about how readily actions get started and how well they are held back under interference, not about trigger failures during mind wandering.

Why the two findings are often linked, and where the link stops

The intuitive bridge is that ADHD involves frequent mind wandering, and mind wandering in healthy adults impairs the triggering of inhibition, so ADHD might combine the two. Adults with ADHD do report excessive mind wandering, and in a clinical sample of 159 medication-free adults, excessive mind wandering and rumination mediated the path from ADHD symptoms to anxiety and depression [3]. That establishes mind wandering as a meaningful, measurable feature of adult ADHD, but it was assessed with questionnaires, not with a stopping task, so it says nothing about trigger failures.

A perspective piece argues that mind wandering research could usefully inform how we study sluggish cognitive tempo and its relationship to ADHD, treating the overlap as a promising research direction rather than a settled mechanism [4]. Read together, these strands make the hypothesis reasonable, but the specific claim that ADHD produces more trigger failures via mind wandering remains untested in the studies available.

What a direct test would need to show

To answer the question properly, a study would need to measure mind wandering and trigger failures in the same people with and without ADHD, ideally separating the launch of the brake from its implementation. The healthy-adult result gives a template: mind wandering raised trigger failures and accounted for most of the stopping slowdown [1]. The ADHD studies show the outcome measures exist and differ by group [2][5], and the adult study shows mind wandering can be quantified in ADHD [3]. What is missing is the overlap: one design that puts all three pieces together.

Until then, the honest reading is that laboratory findings support a plausible pathway from mind wandering to trigger failures in general, and separate findings show ADHD-related differences in inhibition and in mind wandering. The direct ADHD trigger-failure link is a hypothesis worth testing, not a demonstrated fact.

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