Evaluation of the Relationship Between Medication, Eye Movements, and Autonomic Nervous System Functions in Children and Adolescents With ADHD

An increasing number of children are being diagnosed with ADHD, and the demand for ADHD medication has been rising. Although ADHD medication is often effective, this is unfortunately not the case for all children and adolescents with ADHD; furthermore, the majority of those who use the medication experience side effects of some kind. There are currently no known factors that are clearly linked to whether ADHD medications will be effective or cause significant side effects. The healthcare system therefore has limited ability to provide recommendations on ADHD medication at the individual level, which means that most children and adolescents with ADHD try medication. Studies show that 35% of children aged 4-11 and 53% of 12-17-year-olds discontinue ADHD medication within a year. Perhaps these children and adolescents could have avoided fruitless treatment attempts if the healthcare system had been able to provide better recommendations regarding when ADHD medications are most likely to be effective and tolerable treatment options. This, combined with reports of rising mental health issues and an avalanche-like increase in demand for child and adolescent psychiatric services, makes it particularly urgent to develop methods for offering effective interventions to the right patients as specifically as possible.

Previous studies have not consistently identified factors (neither genetic nor other factors such as gender, age, symptom severity, symptom profile, or comorbidities) that are linked to the efficacy or side effects of ADHD medications.

In this project, we will investigate whether the efficacy and side effects of ADHD medications are linked to eye movements or activity within the autonomic nervous system. The autonomic nervous system is the part of our nervous system that is not under our conscious control. It controls many bodily functions such as pupil size, heart rate, blood pressure, and reactions to stress.

Eye and pupil movements are measures of where an individual's attention is directed and how activated the brain is. ADHD is a condition in which the individual has difficulty regulating attention and activity. Therefore, there may be reason to believe that eye movements could be significant in the treatment of ADHD, even though this has never been studied before. Nor has the connection between the autonomic nervous system and the effects of ADHD medications been studied previously, even though changes in heart rate and blood pressure are among the common side effects of ADHD medications.

We will invite children and adolescents who are about to begin ADHD medication. Before they start taking the medication, we will measure eye movements, pupil dilation, and the pupil's reaction to light using so-called eye-tracking technology. This is done by having the child or adolescent look at a screen and follow certain instructions while the pupil's movements are measured. We will also measure heart rate variability, i.e., how much the pulse varies, which can be done by continuously measuring the pulse for 10 minutes. We will investigate whether there is a correlation between the characteristics of these eye movement, pupil, and heart factors before medication begins and the extent to which the medication produces effect and side effects. We will also analyze how these factors are affected by the medication.

The advantage of these factors is that they can be measured without causing pain. Furthermore, they are objective because they measure time and distance and are therefore not dependent on anyone's personal perceptions, as is so often the case with the rating scales otherwise used in psychiatry.

If we can identify correlations between eye movements and activity in the autonomic nervous system and how ADHD medications affect children and adolescents with ADHD, there is a possibility that this could be used to provide better recommendations regarding ADHD medication. Many children could then be recommended other interventions first and avoid unnecessary and unpleasant drug treatments.