June 30, 2021
All Swedish residents have their health records tracked through unique personal identity numbers. That makes it possible to identify psychiatric and medical disorders with great accuracy across an entire population, in this case encompassing more than five and a half million adults aged 18 to 64. A subgroup of more than 1.6 million persons between the ages of 50 and 64 enabled a separate examination of disorders in older adults.
Slightly over one percent of the entire population (about 61,000) was diagnosed with ADHD at some point as an adult. Individuals with ADHD were nine times as likely to suffer from depression as were adults not diagnosed with ADHD. They were also more than nine times as likely to suffer from anxiety or a substance use disorder, and twenty times as likely to be diagnosed with bipolar disorder. These findings are very consistent with reports from clinical samples in the USA and Europe.
Adults with ADHD also had elevated levels of metabolic disorders, being almost twice as likely to have high blood pressure, and more than twice as likely to have type 2 diabetes. Persons with ADHD but without psychiatric comorbidities were also almost twice as likely to have high blood pressure, and more than twice as likely to have type2 diabetes.
Similar patterns were found in men and women with ADHD, although comorbid depression, bipolar disorder, and anxiety were moderately more prevalent in females than in males, whereas substance use disorder, type 2 diabetes, and hypertension were more prevalent in males than in females.
ADHD was less than a third as prevalent in the over-50 population as in the general adult population. Nevertheless, individuals in this older group with ADHD were twelve times as likely to suffer from depression, anxiety, or substance use disorders, and more than 23 times as likely to be diagnosed with bipolar disorder as their non-ADHD peers. They were also 63% more likely to have high blood pressure, and 72% more likely to have type 2 diabetes.
The authors noted, "Although the mechanisms underlying these associations are not well understood, we know from both epidemiologic and molecular genetic studies that a shared genetic predisposition might account for the coexistence of two or more psychiatric conditions. In addition, individuals with ADHD may experience increased difficulties as the demands of life increase, which may contribute to the development of depression and anxiety." As for associations with hypertension and type 2 diabetes, these "might reflect health risk behaviors among adult patients with comorbid ADHD in addition to a shared biological substrate. As others have noted, inattention, disinhibition, and disorganization associated with ADHD could make it difficult for patients to adhere to treatment regimens for metabolic disorders." They concluded that "Clinicians should remain vigilant for a wide range of psychiatric and metabolic problems in ADHD affected adults of all ages and both sexes."
Qi Chen, Catharina A. Hartman, Jan Haavik, Jaanus Harro, Kari Klungsøyr, TorArne Hegvik, Rob Wanders, Cæcilie Ottosen, Søren Dalsgaard, Stephen V. Faraone, Henrik Larsson, “Common psychiatric and metabolic comorbidity of adult attention-deficit/hyperactivity disorder: A population-based cross-sectional study,” PLoSONE (2018), 13(9): e0204516. https://doi.org/10.1371/journal.pone.0204516.
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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