Understanding the Link Between Circadian Rhythm Dysfunction and ADHD in Children

Attention-deficit/hyperactivity disorder (ADHD) is a common and persistent psychiatric condition in children, often leading to significant personal and economic burdens. Despite the success of medication and behavioral treatments, many children with ADHD continue to experience substantial difficulties in school, at home, and with friendships. 

We believe that circadian rhythm is an overlooked factor in the experience of children with ADHD and that wearable sensors show promise for identifying circadian rhythm dysfunction. If addressed, circadian rhythm dysfunction may facilitate more personalized treatments of ADHD.

The Challenge of Clinical Variability in ADHD Treatment

One of the major challenges in treating ADHD is the variation that exists between children. Children with ADHD exhibit a wide range of symptoms, have varied cognitive difficulties, and often have co-occurring mental health disorders. This variability complicates the development of effective treatments that address the functional difficulties associated with ADHD.

The Role of Sleep Disturbances in ADHD

Sleep disturbances, which are common among children with ADHD, contribute to clinical variability. Common sleep disturbances include resisting bedtime, difficulties falling asleep, and irregular sleep patterns (i.e., inconsistent bed and wake times). Sleep disturbances contribute to daytime sleepiness, make ADHD symptoms worse, and undermine cognitive and academic performance. Current best-practice treatments for ADHD rarely target sleep problems. 

Behavioral vs. Biological Pathways of Sleep Disturbances in ADHD

Broadly speaking, sleep problems in ADHD arise from two distinct pathways: behavioral and biological. In the behavioral pathway, sleep disturbances are a result of ADHD symptoms and co-occurring mental health conditions, including disorganization (which leads to inconsistent bedtimes) and oppositional behavior (which leads to bedtime resistance). In the biological pathway, children with ADHD may have a natural inclination to go to sleep and to wake up later than is practical given parental work and school schedules. For some children, factors from both behavioral and biological pathways may contribute to their sleep problems. Understanding the varied reasons for sleep disturbances among children with ADHD may inform new thinking about personalized treatments for ADHD.

Assessing Sleep Disturbances in ADHD with Wearable Sensor Technology

To the extent that clinical assessments of ADHD currently consider sleep disturbances, they are more likely to consider the behavioral than the biological pathway due to the ease of assessment. The behavioral pathway can easily be addressed using parent reports regarding bedtime routines and behavior. 

In contrast, the gold standard measure of the biological pathway involves taking samples of saliva over multiple hours in low light conditions, which is burdensome to implement. Notably, advances in wearable sensors offer new opportunities for assessing circadian function in children with ADHD. These non-invasive sensors measure core body temperature, heart rate, and patterns of rest and activity, which may provide valuable insights into the child's circadian rhythm with less burden. 

Personalized Treatment Approaches for Sleep Disturbances in ADHD

Distinguishing children with ADHD with respect to behavioral and biological contributors to sleep disturbances may pave the way for personalized treatments. For example, behavioral sleep treatments may be most appropriate for children with ADHD whose sleep problems stem from behaviors such as disorganization or oppositional defiance. In contrast, among children with ADHD sleep problems of biological origin, therapies that improve circadian function may be more appropriate. For example, blue light therapy may help realign their biological clocks with their social schedules. Personalized treatments that address the underlying biological mechanisms of ADHD have the potential to improve long-term educational, interpersonal, and occupational outcomes for children with ADHD.

Advancing ADHD Treatment with Wearable Technology

There is growing interest in exploring circadian rhythm dysfunction as a contributing factor to clinical variability within ADHD. Advances in wearable technology may be especially useful in reducing the burden associated with traditional methods of assessing circadian dysfunction. Beginning to assess both the presence and nature of sleep disturbance as a standard part of clinical assessments of ADHD may facilitate personalized interventions. This approach not only holds the potential to improve symptoms but also to enhance the overall quality of life for children and their families.