This is the second article in a three part ADHD regulation series for parents.
Understanding Executive Functions
Parents often tell me their child clearly knows what they're supposed to do, yet somehow doesn't manage to do it. They may recall extraordinary detail about something they love, yet forget an instruction given moments ago. They may know an assignment is due next week, understand exactly what's required, and still forget about it until the deadline is close.
Regulating Thinking and Behaviour in ADHD
Executive functions are the mental control processes that help us work towards a goal - holding information in mind, organising ourselves, planning, resisting the first impulse, starting tasks, and monitoring our own progress. They are, in effect, our brain's self-regulation system: even when knowledge and intention are clearly present, the process of turning them into organised action can be genuinely difficult. That's why parents sometimes say, "I know he can do it. I just don't understand why he doesn't." Current models of ADHD increasingly frame the disorder this way - not as a single deficit, but as a difficulty coordinating several regulatory systems, including attention, cognitive control, and emotion, together (see, for example, recent integrative neurocognitive models linking brain circuitry, metacognitive control, and emotion regulation in ADHD).
At INPSYGHT, ADHD and psychometric assessment can help measure the effectiveness of different cognitive processes - attention, working memory, long-term memory, and processing speed - to show whether a child's difficulties fit a broader ADHD pattern or whether another factor needs to be understood.
Working Memory Is Not the Same as Long-Term Memory
Working memory is the temporary mental "holding space" we use to keep information in mind while doing something with it - very different from long-term memory, where a child with ADHD may have excellent recall for a favourite subject or an event from years ago, yet forget what a parent asked 30 seconds earlier. A meta-analysis of working memory in children with ADHD confirms this is a consistent, measurable weakness as a group, affecting multi-step instructions, mental arithmetic, and picking a task back up after an interruption (Martinussen et al., 2005).
Why Executive Difficulties Can Look Like Behaviour Problems
Executive difficulties are often most visible in family and school life - losing belongings, forgetting equipment, starting before reading instructions, or becoming overwhelmed when several things need organising at once. Inhibition problems can look like calling out or grabbing something before thinking; task-initiation difficulties can look like laziness or defiance, when the real issue is activating and organising behaviour, not motivation.
Not every child's profile looks the same. One child may have marked working-memory difficulties but strong planning skills; another may perform well on formal testing but struggle to apply those skills consistently when tired or distracted. This variability is well documented: twin research examining reading disability and ADHD together found that each condition involves multiple, partly independent cognitive weaknesses rather than one core deficit - reading difficulties were linked to phoneme awareness, verbal reasoning, and working memory, ADHD to inhibitory control, and the two shared a common, genetically influenced weakness in processing speed (Willcutt et al., 2010). This is part of why some children who struggle with attention also struggle disproportionately with tasks like handwriting or written composition - recent research found that processing speed alone accounted for nearly a fifth of the link between inattention symptoms and weaker writing composition, more than working memory or inhibition combined (Trane, Paulich, Dokuru & Willcutt, 2025).
Willcutt and colleagues' major review of the executive function theory of ADHD reached a similar conclusion at a broader level: executive difficulties are important for understanding ADHD as a group, but they are neither universal nor sufficient on their own to explain every case. This is exactly why comprehensive ADHD testing at INPSYGHT looks at the individual pattern rather than assuming every child's executive profile is the same.
What Else Affects Regulation Day to Day?
It's worth noting that executive regulation isn't fixed - it fluctuates with sleep and physical activity. Research specifically in children and adolescents with ADHD has found that both higher levels of moderate-to-vigorous physical activity and longer sleep duration are associated with meaningfully better everyday executive functioning (Liang et al., 2026). This doesn't replace a formal assessment or treatment plan, but it's a useful, low-risk piece of the picture worth discussing when we look at what's making regulation harder or easier for a particular child.
The useful question is not "why doesn't my child just do it?" but: "Which parts of regulating thinking and behaviour are difficult for this child, and how are they affecting everyday life?" That understanding gives parents and schools something far more useful than telling a child to try harder - and it's what I aim to clarify through ADHD assessment at INPSYGHT in Manly and Belrose.
References
Martinussen R, Hayden J, Hogg-Johnson S, Tannock R. (2005). A meta-analysis of working memory impairments in children with ADHD. Journal of the American Academy of Child & Adolescent Psychiatry, 44, 377–384.
Willcutt EG, Doyle AE, Nigg JT, Faraone SV, Pennington BF. (2005). Validity of the executive function theory of ADHD: a meta-analytic review. Biological Psychiatry, 57, 1336–1346.
Willcutt EG, Betjemann RS, McGrath LM, Chhabildas NA, Olson RK, DeFries JC, Pennington BF. (2010). Etiology and neuropsychology of comorbidity between RD and ADHD: the case for multiple-deficit models. Cortex, 46, 1345–1361.
Trane FE, Paulich KN, Dokuru DR, Willcutt EG. (2025). Contributions of working memory, inhibition, and processing speed to writing composition in ADHD. Developmental Neuropsychology, 50(1), 1–23.
Liang X et al. (2026). Associations between accelerometer-measured physical activity and sleep duration and health indicators in children and adolescents with ADHD. Journal of Exercise Science & Fitness, 24, 200429.
Faraone SV et al. (2021). The World Federation of ADHD International Consensus Statement. Neuroscience & Biobehavioral Reviews, 128, 789–818.