December 17, 2021
A team of Spanish researchers performed a systematic search of the medical literature and found 28 studies that could be included in a series of meta-analyses of specific measures of sleep impairment. Except for a single meta-analysis with eight studies and 1,713 participants, however, all involved just three to five studies apiece, with anywhere from 121 to just over a thousand participants.
The team examined three sorts of measures:
· Subjective measures, based on self-reporting by ADHD patients.
· Polysomnography is an objective sleep study in which the subject is wired up and studied by technicians in a lab, usually overnight, monitoring multiple body functions, such as brain activity, eye movements, muscle activation, and heart rhythm.
· Actigraphy, a non-invasive objective means of monitoring sleep. The subject wears an actimetry monitor, which is usually worn like a wristwatch on the non-dominant arm. Because it is minimally intrusive, the subject may wear it for a week or more while engaging in normal activities.
In the subjective measures, adults with ADHD generally reported substantially higher sleep impairments than non-ADHD controls. In the largest meta-analysis, covering eight studies and 1,713 participants, adults with ADHD reported moderately longer latency times for falling asleep than controls. In meta-analyses of five studies with between 834 and 1,130 participants, they also reported moderately poorer sleep quality, more frequent night awakenings, being moderately less rested upon awakening in the morning, and moderate-to-strongly greater daytime sleepiness. There was no significant difference in perceived sleep duration.
Polysomnography measures, on the other hand, failed to confirm these subjective impressions. No significant differences were found between adults with ADHD and controls for the initial latency period until onset of sleep, sleep efficiency, waking after the onset of sleep, total sleep time, stage one or stage two sleep, slow-wave sleep, REM (rapid eye movement) sleep, and latency period until REM sleep.
As mentioned above, polysomnography is conducted in lab settings, and therefore inevitably diverges from normal patterns of behavior. Actigraphy helps bridge that gap, by monitoring normal behavior, though with more limited types and precision of data analysis.
And indeed, a meta-analysis of four studies with 222 participants confirmed self-reports that sleep efficiency was moderate to strongly lower in adults with ADHD and that the latency period until the onset of sleep was markedly longer. On the other hand, it found no significant difference in true sleep.
The researchers also looked at prevalence statistics. Whereas the prevalence of sleep-onset insomnia in the general population has been reported in the range of 13 to 15 percent, a meta-analysis of four studies with 466 participants found fully two-thirds of adults with ADHD reporting insomnia, a greater than four-to-one ratio. Similarly, a meta-analysis of three studies with 458 participants found one-third reporting daytime sleepiness, which is twice the rate reported in the general population.
There was no sign of publication bias in any of these results. The authors cautioned, however, about the small number of studies involved, stating this "compromises the generalizability of the findings." Also, some studies included patients undergoing pharmacological treatment for ADHD, "increasing the risk of confounding results."
Moreover, "Sleep onset latency and sleep efficiency were not significantly impaired in the polysomnography, which was incongruent with the actigraphy results. This may be due to a difference in the evaluation context. Whereas polysomnography is considered the gold-standard measure to objectively assess sleep architecture, actigraphy shows a more ecological approach, with the evaluation being conducted in a more naturalistic context for a longer period. However, actigraphy has more environmental influence, which can compromise the data recorded and the interpretation of the results, whereas, in polysomnography, multiple variables can be controlled in the laboratory setting to increase the internal validity of the results. On the contrary, polysomnography studies can produce artifacts due to the unusual circumstances in the setting, so results may need to be interpreted with caution."
The authors concluded, "The results found in the present study show the relevance of addressing sleep concerns in adult populations diagnosed with neurodevelopmental conditions."
Jorge Lugo, Christian Fadeuilhe, Laura Gisbert, Imanol Setiena, Mercedes Delgado, Montserrat Corrales, Vanesa Richarte, Josep Antoni Ramos-Quiroga, "Sleep in adults with autism spectrum disorder and attention-deficit/hyperactivity disorder: A systematic review and meta-analysis," EuropeanNeuropsychopharmacology (2020),https://doi.org/10.1016/j.euroneuro.2020.07.004.
There has been consistent evidence of an association between ADHD and subjectively reported sleep problems even in patients not medicated for the disorder. There have also been studies using wrist-worn actigraphy (a wrist watch-like device that measures gross motor activity) and sleep lab-based polysomnography that measure objective sleep parameters.
What has been missing are large population-based cohort studies to explore the prevalence rates of different sleep disorders and medical prescriptions in ADHD.
Methods Used:
Sweden has a single-payer health insurance system and a series of national population registers that track virtually its entire population. Using the Swedish Total Population Register, a local research team created a cohort of all 6,470,658 persons born between 1945 and 2008. They linked this to the Swedish National Patient Register, which includes inpatient hospitalizations from 1975 to 2013, and outpatient specialist diagnoses from 2001 to 2013, to identify diagnoses of sleep disorders. They also linked to the Prescribed Drug Register, covering 2005 to 2013, to identify prescriptions for sleep medications.
Summary of Findings:
Overall, persons with ADHD were eight times more likely to be diagnosed with any sleep disorder relative to normally developing peers. Broken down by age, adolescents with ADHD were 16 times more likely to receive such diagnoses, young adults (18-30) twelve times more likely, children and mid-age adults (31-45) eight times more likely, and older adults six times more likely.
Broken down by specific sleep disorder diagnoses, relative to normally developing peers, persons with ADHD were:
As for sleep medication, relative to normally developing peers, persons with ADHD were:
Conclusion:
The team concluded, “Our findings also suggest that greater clinical attention should be directed towards addressing sleep problems in individuals with ADHD. This entails implementing proactive measures through sleep education programmes and providing both pharmacological and non-pharmacological approaches such as cognitive behavioural therapy and parental sleep training.”
Attention is a critical determinant of academic achievement, influencing domains such as language, literacy, and mathematics. To explore whether physical activity can improve attention in children with ADHD, an international team conducted a meta-analysis of peer-reviewed studies. The goal was to evaluate the impact of various physical activity regimens on attention-related outcomes in this population.
The researchers performed a comprehensive search of the medical literature to identify studies examining the effects of physical activity on attention in schoolchildren with ADHD. They included 10 studies with a total of 474 participants in their meta-analysis. The studies evaluated two main types of physical activity:
Additionally, they examined variations based on the frequency, duration, and type of control groups used in the studies. To assess consistency, they also analyzed heterogeneity (variability of outcomes) and checked for potential publication bias.
Key findings from the meta-analysis include:
The authors concluded that mentally engaging exercise is more effective than aerobic exercise in improving attention problems in schoolchildren with ADHD. Furthermore, higher frequency and longer duration of physical activity do not necessarily yield better outcomes.
This research underscores the importance of tailoring physical activity interventions to emphasize cognitive engagement over intensity or duration. By refining strategies, educators and parents can better support children with ADHD in achieving academic success. But take note: given the results from controlled studies, it seems clear that if there is a positive effect of exercise, it is very small so should not replace standard treatments for ADHD.
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Previous studies have examined how stimulant medications affect the brain in controlled settings, but less is known about their impact in real-world conditions, where children may not always take their medication consistently or may combine it with other treatments. A new study leverages data from the Adolescent Brain Cognitive Development (ABCD) study to explore how real-world stimulant use impacts brain connectivity and ADHD symptoms over two years.
Changes in Brain Connectivity Researchers used brain imaging data from the ABCD study to examine the functional connectivity—communication between brain areas—of six regions within the striatum, a brain area involved in motivation and movement control. They focused on how stimulant use influenced connectivity between the striatum and other networks involved in executive functioning and visual-motor control.
The study found that stimulant exposure was linked to reduced connectivity between key striatal areas (such as the caudate and putamen) and large brain networks, including the frontoparietal and visual networks. These changes were more pronounced in children taking stimulants compared to those who were not medicated, as well as compared to typically developing children. Importantly, this reduction in connectivity seemed to regulate certain brain networks that are typically altered in children with ADHD.
Symptom Improvement In addition to brain changes, 14% of children taking stimulants experienced a significant reduction in ADHD symptoms over the two-year period. These children showed the strongest connectivity reductions between the right putamen and the visual network, suggesting that stimulant-induced connectivity changes may contribute to improvements in visual attentional control, which is a common challenge for children with ADHD.
Why This Matters This study is one of the first to examine how stimulant use in real-world conditions affects brain networks in children with ADHD over time. The findings suggest that stimulants may help normalize certain connectivity patterns associated with ADHD, particularly in networks related to attention and control. These insights could help clinicians better understand the potential long-term effects of stimulant treatment and guide personalized approaches to ADHD management.
Conclusion Stimulant medications appear to alter striatal-cortical connectivity in children with ADHD, with some changes linked to symptom improvement. This research highlights the potential for stimulant medications to impact brain networks in ways that support attention and control, highlighting the importance of understanding how real-world medication use influences ADHD treatment outcomes.
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