Impaired reward processing could influence the presentation of sleep disturbances for patients with ADHD.
New research suggests a further understanding as to why patients with attention deficit hyperactivity disorder (ADHD) suffer from greater rates of sleep issues, including insomnia and excessive sleepiness.
A team, led by Sachin Lokuge, S.T.A.R.T. Clinic for Mood and Anxiety Disorder, examined whether impaired reward processing evidenced by anhedonia is linked to sleep disturbances and whether this association is more pronounced in ADHD patients.
The data was presented in a poster during the 2021 American Psychiatric Association Annual Meeting.
Impaired sleep is a known risk factor for several negative health outcomes, such as deficits in executive function, attention, and impulse control, which all happen to be symptoms of ADHD. About half of ADHD patients report sleep disturbances, with delayed sleep onset being the most commonly reported symptom.
Sleep deprivation is also linked to reduced dorsolateral prefrontal activity, as well as difficulty regulating attentional resources. This could help explain the inability to attend to a stimulus in the presence of distractions or engage in goal-directed behavior.
“These deficits in reward-related brain function may also contribute to the development of depressive symptoms through the blunted experience of positive affect,” the authors wrote.
In the study, the researchers assessed 89 ADHD patients using the MINI Plus ADHD module 5.0.0 and measured sleep anomalies, including sleepiness (ESS), insomnia (ISI), and quality (SQS). In addition, they measured anhedonia using the FCPS and SHAPS.
Overall, the patients with ADHD reported greater impairment on sleep quality (P = 0.009), insomnia (P = 0.004), and sleepiness (P = 0.029).
The patients with higher sleep quality scores also had lower SHAPS scores, regardless of ADHD diagnosis (β = -0.235; P = 0.012).
The association of ADHD diagnosis and sleepiness scores was influenced by SHAPS scores (b = 0.199, P = 0.039), to where the significance of the relationships increased with higher SHAPS scores.
“Patients with ADHD exhibited greater insomnia, excessive daytime sleepiness, and reduced sleep quality, consistent with studies indicating higher prevalence of insomnia in ADHD patients and greater risk of ADHD among individuals with narcolepsy,” the authors wrote. “The relationship between ADHD and daytime sleepiness was increased at higher levels of anhedonia, suggesting that impaired reward processing may influence the presentation of sleep disturbances in ADHD patients.”
The researchers suggest future studies focus on the role of reward processing in sleep disturbance across different psychiatric disorders.
Earlier this year, researchers found timing and regularity of sleep could influence symptoms and social functioning for ADHD patients.
Irregular sleep was linked to greater patient- and parent-reported symptoms of ADHD (P = .01; P <.001, respectively), as well as lower social function (P = .003; P = .02, respectively). Lower academic functioning was also associated with irregular sleep, as per both patient and parent reports.
Investigators concluded that both sleep regularity and timing may be crucial to adolescent patients with ADHD achieving ideal attention and daytime functioning. In fact, both outcomes could inform potential intervention and interventional studies.
The study, “The Moderating Effect of Reward Processing on the Relationship Between Sleep and ADHD,” was published online by the American Psychiatric Association.