December 11, 2021
Taiwan has a single-payer healthcare system that covers virtually every inhabitant (99.5%). That makes it relatively easy to track healthcare issues using its comprehensive National Health Insurance Research Database.
This database maintains a subset, the Longitudinal Health Insurance Database (LHID), consisting of a million persons, with no significant differences in sex, age, or healthcare use from the parent database.
A Taiwanese research team used the LHID to identify 114,486 individuals diagnosed with ADHD from 1997 to 2013. It then compared their motor vehicle (including motorcycles, which are extremely common in Taiwan) crash patterns with 338,261 normally developing controls from the same database.
Adjusting for sex, age, and psychiatric comorbidities, persons with ADHD were about a fifth (19%)more likely to be in traffic crashes. Breaking it down further by sex, women with ADHD were no more likely to be in crashes, but men with ADHD were about a quarter (24%) more likely than their healthy counterparts.
Since the database also tracks pharmaceutical prescriptions, the team also looked into the effect of methylphenidate (MPH), the medication that is the first-line treatment for ADHD under Taiwanese guidelines, and the only approved stimulant. Atomoxetine, a non-stimulant, is used where MPH is either ineffective or not indicated for any other reason and is only used in 4% of all cases.
Of the 114,486 persons diagnosed with ADHD, 89,826 used MPH, and 24,660 did not.
Compared with persons with ADHD who were not on methylphenidate, those with ADHD who were on MPH for 180 days (roughly half a year) or less had 77% fewer accidents, and those on MPH for over 180 days had 93% fewer accidents. This strong dose-response relationship is suggestive of a causal relationship, with MPH perhaps reducing impulsive behavior, particularly among young men with ADHD.
The team also conducted within-person analyses, comparing times when persons with ADHD were taking MPH with periods when they were not. These showed no effect within 30 days of use, rising to a 65%reduction in crashes within 60 to 90 days of use, which was barely outside the 95% confidence interval (p = .07), very likely because of "the extremely low incidence of transport accidence (i.e. 0.6%)enlarged the confidence interval."
The authors concluded, "All registration medical claim data came from the nationally-representative sample of NHI, minimizing the selection and recall bias. By excluding transport accidents before ADHD diagnosis, we have precluded the reverse association between ADHD and road traffic accidents as much as possible. The advantage of the between-subjects comparison was that we were able to examine the MPH effect in different dose groups. However, confounding by indication cannot be eliminated. For example, those with a severe degree of ADHD symptoms, an exhibition of risky behaviors, or comorbid with other psychiatric illnesses were more likely to be prescribed medication. Hence, we also performed within-subject comparisons to adjust for time-invariant factors."
Transport safety thus offers another compelling reason to treat ADHD symptoms. Methylphenidate in particular seems to be especially effective in reducing traffic fatalities and injuries.
Yi-Chun Liu, Vincent Chin-Hung Chen, Yao-Hsu Yang, Yi-LungChe, and Michael Gossop, "Association of psychiatric comorbidities with the risk of transport accidents in ADHD and MPH," Epidemiology and PsychiatricSciences30 (2021), e14, 1-9,https://doi.org/10.1017/S2045796021000032.
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.”
Congenital cleft lip and palate (CCLP) are birth defects associated with genetic and environmental factors. The latter include heavy maternal consumption of alcohol and fetal exposure to retinoid drugs derived from vitamin A.
Methods:
Taiwan has an island-wide single-payer health insurance system that reaches over 99% of the population. To explore the relationship between CCLP and various psychiatric disorders including ADHD, a Taiwanese study team used the island’s National Health Insurance Research Database to identify all 1,158 children and adolescents with CCLP during a ten-year period. They matched them ten-to-one with 11,580 age and sex-paired controls without CCLP.
Summary of Results:
Further adjusting for demographic data (income, residence) and family history of major psychiatric disorders, children and adolescents with CCLP were more than seven times more likely to be diagnosed with ADHD during the follow-up period than controls. Patients with both cleft palate and cleft lip were more than nine times more likely to be subsequently diagnosed with ADHD than controls.
Patients with CCLP were also six times more likely to be diagnosed with autism spectrum disorder and more than seven times as likely to be diagnosed with schizophrenia as non-CCLP controls. They were also more likely to be diagnosed with bipolar disorder or major depressive disorder, but these results did not reach statistical significance.
Conclusion:
This study highlights a significant association between congenital cleft lip and palate (CCLP) and an increased risk of developing ADHD, with CCLP patients being more than seven times as likely to be diagnosed with the disorder. Additionally, CCLP was linked to a higher prevalence of other psychiatric conditions, including autism spectrum disorder and schizophrenia. These findings underscore the importance of monitoring mental health in individuals with CCLP and call for further research into the risk factors connecting these birth defects with psychiatric disorders.
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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