How does stimulant medication actually work on thinking skills?

We have previously posted about ‘myths around ADHD’ covering issues such as the lifespan nature of ADHD symptoms, common beliefs that ADHD is seen typically on its own and that those with ADHD are similar to each other. Another myth is that ADHD mainly affects behaviour. Our research, however, and that of many other groups has shown that thinking difficulties like memory, attentional control and planning are key difficulties for many children with ADHD.

Other myths around ADHD extend to stimulant medication, a common treatment for ADHD. So how do stimulants actually work? There is now considerable research evidence looking at how stimulants work. How do you know where to start in terms of which of these research papers should be considered? A good place to start is to look at whether there have been any reviews on the topic that have been done in a systematic way (what is called a ‘systematic review’) – this is like a study of studies. It brings together and reviews all papers on a topic and as part of the process assesses the quality of the studies and for example tries to find out if the studies are at risk of bias. It is even better if there is what is called a ‘meta-analysis’ on the topic. A meta-analysis merges the findings of individual studies and statistics are used to arrive at an overall effect across the studies.

Last year a meta-analysis was published on the topic of stimulant medication and thinking skills in children with ADHD. They found that stimulant medication improved a range of thinking skills – what are called ‘executive functions’. They include aspects of thinking such as ‘working memory’ (the mental workspace where you hold and organise information for a brief time) and ‘cognitive flexibility’ (being able to switch from thinking about different concepts or doing different parts of task). We know many children with ADHD have difficulties in these thinking skills and it is clear that the improvements we see in many children with ADHD while on medication likely reflect them being able to use their ‘executive function’ skills better. Larger doses of medication were not found to improve these particular thinking skills more than the effect of small doses.

Our own research has shown that stimulant medication improves these executive functions but has also highlighted that stimulants act on self-regulation which is a broader concept. Basically we found that despite the common understanding that this medication acts by slowing down the child so they can stop and think better actually this is too simple an explanation. We found that stimulants slowed down performance on tasks where it is good to stop and think (letting them make a plan or organise their thoughts). But stimulants also actually speeded up performance – this time on a task where the child was encouraged to perform the task as quickly as possible (doing so doesn’t usually cause more errors). So it appears that stimulants improve ‘self-regulation’ – allowing the child to act more appropriately to the requirements of the task they are doing.

While the executive function meta-analysis study looked at quite a range of thinking skills many everyday thinking skills such as planning, problem solving, time management, and self-monitoring were not examined. This reflects a lack of research studies that have examined these broader thinking skills. EPIC has been developed to help support the development of all of these thinking skills. Ideas for how to facilitate understanding of an individual child’s thinking skills and strategies to support them can be found in our free downloadable booklets. EPIC focuses on the child as a individual as children who are ‘neurodivergent’ (when someone’s thinking, learning or behaviour differs from what is considered typical) differ from one another in their thinking skills. This may be due to the presence of a second or even third co-occurring condition (e.g. having a diagnosis/symptoms of ADHD versus both ADHD + autism). Whatever the reason it is really important we understand the thinking skills of each individual neurodivergent child as an individual. EPIC materials can be used to help identify what lies behind an individual child’s difficulties whether that is with the school experience, learning, relationships with their peers and/or generally navigating everyday life situations. At the moment these booklets relate to ADHD and DCD specifically but they can be used for any child who struggles with these thinking difficulties and indeed we are currently working on booklets and videos that are tailored to all children who are neurodivergent.

Visual production credit: photographer monkeybusiness images via Getty images.

Author: Sinead Rhodes

Senior Research Fellow, Centre for Clinical Brain Sciences, University of Edinburgh Founder and Chair of Research the Headlines RSE Young Academy of Scotland

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