ADHD Questions
Does ADHD affect reaction time?
Charles Li, MD
May 12, 2023
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ADHD has been linked to cognitive deficits beyond its core symptoms.
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Studies have shown that those with ADHD have slower reaction times, including highly intelligent individuals.
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Having anxiety with ADHD can make reaction times even slower.
Most of us know about the effect that ADHD has on attention and hyperactivity. Research is starting to show that it can affect many other aspects of cognition as well, including reaction time.
One study found that even among highly intelligent individuals with ADHD, 42% suffered from severely slower reaction times:
Executive function impairments in high IQ children and adolescents with ADHD
How ADHD affects reaction time
One reason behind ADHD’s effect on reaction time may be the link between ADHD and the way we think.
Experts have known for a while that ADHD affects the way we think through its effect on executive function, the higher level thought processes we use for problem-solving:
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There is general agreement that there are three core EFs....inhibition [inhibitory control, including self-control (behavioral inhibition) and interference control (selective attention and cognitive inhibition)], working memory (WM), and cognitive flexibility (also called set shifting, mental flexibility, or mental set shifting and closely linked to creativity). From these, higher-order EFs are built such as reasoning, problem solving, and planning
It turns out that this effect also extends to reaction time, which is not traditionally thought of as a component of executive function.
A meta-analysis found that individuals with ADHD tend to have significantly slower reaction times:
The effect of ADHD on reaction time was found to be very similar to the effect of ADHD on executive function:
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We do not believe that our similar results in the EF and non-EF domains indicate that we should discard the possible EF explanation for ADHD altogether, but it seems high time for some changes in the field. For one thing, it seems, now more than ever, necessary to develop reliable and valid measures of EF.
Anxiety and reaction time in ADHD
Anxiety may play a role in reaction time in ADHD.
Previous studies have shown links between anxiety and ADHD symptoms. Having anxiety and ADHD together affects how we experience ADHD.
Regarding reaction time, anxiety can make reaction times even longer for those with ADHD and anxiety.
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Two recent texts on comorbid conditions seen in ADHD (Brown, 2000; Pliszka et al., 1999) have posited that anxiety may inhibit impulsivity while making attentional tasks worse. Pliszka et al. (1999, p. 155) reviewed their own studies showing that children with ADHD and anxiety are less likely to display off-task and hyperactive behavior and have longer reaction times than pure ADHD children.
Pliszka et al. 1999
Brown, 2000
One study that tested ADHD symptoms in those with and without anxiety found that those with anxiety had less impulsiveness but longer reaction times when they were presented with distractions: