October 16, 2021
What are the links between ADHD and physical ailments in adults? And, where such links exist, how can we tease out where they are due to genetics, shared environment, or unshared environmental influences?
An international research team used the Swedish population and health registers to explore these links in an entire national population. They were able to do this because Sweden has a single-payer national health insurance system, cross-referenced with the population and other national registries through personal identification numbers.
This study identified full-sibling and maternal half-sibling pairs born from 1932 through 1995, through the Population and Multi-Generation Registers. This yielded a total of 4,789,799 individuals - consisting of 3,819,207 full-sibling pairs and 469,244 maternal half-sibling pairs, and 1,841,303family clusters (siblings, parents, cousins, spouses). Roughly half were men, the other half women.
After adjusting for sex and birth year, those with ADHD were at significantly higher risk of a wide range of physical ailments, when compared with individuals without ADHD:
· Over four times as likely to have sleep disorders or develop alcohol-related liver disease;
· Roughly three times as likely to develop the chronic obstructive pulmonary disease, epilepsy, and fatty liver disease;
· Over two and a half times more likely to become obese.
Overall, ADHD was significantly associated with 34 of the 35 physical diseases studied, rheumatoid arthritis being the only exception.
Comparing men with women, women with ADHD were at significantly greater risk of atrial fibrillation, urolithiasis, sleep disorders, and asthma than men with ADHD. Conversely, men with ADHD faced a greater risk of thyroid disorder than women with ADHD.
Between-sibling analyses showed that full siblings of individuals with ADHD were at significantly increased risk for 27 of the 35 physical ailments, suggesting that shared familial factors contributed to the co-occurrence of the conditions. This remained true even after adjusting for the occurrence of ADHD in full siblings.
These associations were generally reduced in maternal half-siblings of individuals with ADHD. The associations between full-siblings were significantly stronger than between maternal half-siblings for type 1 diabetes, obesity, kidney infections, back or spine pain, migraine, sleep disorders, asthma, and chronic obstructive pulmonary disease.
Keep in mind that full-siblings on average share half of their genes, whereas maternal half-siblings share only a quarter of their genes. Maternal (as opposed to paternal) half-siblings were chosen as a basis for comparison because they are typically brought up together in the same family setting, and thus are similar to full-siblings in having a shared family environment. Reduced risk in maternal half-siblings would therefore signal a genetic component to the risk.
Given that ADHD is itself a nervous system disorder, it is unsurprising that it correlated most strongly with other nervous system disorders, with a medium effect size (r=.23). Genetic factors explained over a quarter of the correlation, shared environmental factors over a seventh, and non-shared environmental factors the other three-fifths. The latter could point to environmental risk factors that influence both ADHD and nervous system diseases.
Small-to-medium correlations were found with metabolic, respiratory, and musculoskeletal disease groups, with genetic factors explaining roughly two-thirds of the correlation, and non-shared environmental factors most of the rest.
The authors concluded that "adults with ADHD are at increased risk of a range of physical conditions, across circulatory, metabolic, gastrointestinal, genitourinary, musculoskeletal, nervous system, respiratory, and skin diseases. Most physical conditions showed familial associations with ADHD (mainly from genetic factors). Our findings highlight the need for rigorous medical assessment and care in adult patients with ADHD, and suggest long-term consequences of age-related diseases."
Ebba Du Rietz, Isabell Brickell, AgnieszkaButwicka, Marica Leone, Zheng Chang, Samuele Cortese, Brian M D'Onofrio, Catharina A Hartman, Paul Lichtenstein, Stephen V Faraone, Ralf Kuja-Halkola, Henrik Larsson, "Mapping phenotypic and aetiological associations between ADHD and physical conditions in adulthood in Sweden: a genetically informed register study," Lancet Psychiatry (2021), vol. 8, issue 9, 774-783, published online, https://doi.org/10.1016/S2215-0366(21)00171-1.
Recent research suggests that inflammation may play a role in ADHD. Inflammation, marked by elevated proteins and cytokines, affects brain development and structure. Evidence suggests it plays a role in the development of ADHD, making the study of inflammatory markers crucial.
The platelet-to-lymphocyte ratio (PLR) is a cost-effective test for predicting outcomes of chronic inflammation and neuroimmune diseases. Studies show PLR may be an important inflammatory marker in the pathophysiology of ADHD in children.
The Study:
A Chinese study team used the National Health and Nutrition Examination Survey (NHANES) database maintained by the National Center for Health Statistics of the United States to investigate the association between PLR and ADHD in children aged 6–14.
The team identified ADHD through prescriptions of ADHD medications.
After exclusions for missing information, the study encompassed 1,455 children.
The authors adjusted for the following potential confounders: sex, age, race, poverty-to-income ratio, maternal age at childbirth, smoking during pregnancy, asthma, health insurance status, dietary inflammatory index, monocyte count, segmented neutrophil count, eosinophil count, and basophil count.
They also split the PLR results into quartiles, with the first quartile having the lowest readings.
Prescriptions of ADHD medications were twice as frequent among children in the second quartile as they were among children in the first quartile. They were four times as frequent among children in the third quartile than among children in the first quartile.
Conclusion:
The team concluded, “These findings further support the potential role of inflammation in the onset and development of ADHD, providing preliminary evidence for PLR as a potential biomarker for ADHD and suggesting its possible use in identifying high-risk populations. However, considering the limitations of this study, future research should be designed as larger-scale, prospective, multi-center randomized controlled trials to validate these findings and further explore the relationship between inflammatory mechanisms and ADHD.”
In other words, this study suggests that while high PLR values may serve as a potential biomarker for ADHD, particularly in specific high-risk groups, further research is needed to confirm these findings and fully understand the role of inflammation in ADHD development. Larger, more robust studies will be crucial to validating PLR as a reliable tool for identifying at-risk populations.
ADHD is the most prevalent neurodevelopmental disorder. Nearly 1% of pregnant women in the Nordic countries and more than 1% in the United States are prescribed ADHD medications, ranking these among the most commonly used medications during pregnancy. However, the safety of exposing a fetus to ADHD medications is still uncertain, prompting many expectant mothers to stop using them out of fear for their unborn child’s well-being.
The Study:
A European research team conducted a comprehensive nationwide study on the safety of ADHD medications during pregnancy using populations from Sweden and Denmark. The Swedish population was studied first, followed by inclusion of a separate study of the Danish population. Results were then combined through meta-analysis. Nordic countries, with their single-payer national health insurance systems and national population registers, facilitate the tracking of residents’ health from birth to death, thus providing robust data for such studies.
The team accounted for various potential confounders, including maternal age, year of delivery, whether the mother was a first-time parent, self-reported smoking during pregnancy, and any psychiatric history. They also considered psychiatric inpatient or outpatient treatment received within two years before pregnancy, as well as the dispensing of other psychotropic medications during pregnancy, including antidepressants, antipsychotics, antiseizure medications, and anti-anxiety medications. Additionally, they examined the highest level of maternal education and civil status at delivery (married or cohabiting compared to single, divorced, or widowed).
Out of 861,650 Swedish children, 2,257 were exposed to ADHD medications during pregnancy. Another 3,917 were born to mothers who discontinued ADHD medications before pregnancy.
Children exposed to ADHD medications had lower rates of ADHD, autism spectrum disorder, and overall neurodevelopmental disorders; however, none of these differences were significant.
Limiting the analysis to siblings to control for family environmental influences and genetics likewise found no significant differences.
A meta-analysis combining the Swedish results with a separately conducted nationwide population study in neighboring Denmark similarly found no significant differences between children exposed to ADHD medications during pregnancy and children born to mothers who discontinued ADHD medications before pregnancy.
Conclusion:
The team concluded, “Overall, our study provides reassuring evidence that continuing ADHD medication during pregnancy does not increase the risk of long-term NDDs [neurodevelopmental disorders] in offspring."
A new large-scale study has shed light on which treatments for attention-deficit/hyperactivity disorder (ADHD) in adults are most effective and best tolerated.
Researchers analyzed 113 randomized controlled trials involving nearly 15,000 adults diagnosed with ADHD. These studies included medications (like stimulants and atomoxetine), psychological therapies (such as cognitive behavioral therapy), and newer approaches like neurostimulation.
The Findings
Stimulant medications (lisdexamfetamine and methylphenidate) as well as selective norepinephrine reuptake inhibitors (SNRI) (atomoxetine) were the only treatments that consistently reduced core ADHD symptoms—both from the perspective of patients and clinicians. It may be worth noting that atomoxetine, while effective, was less well tolerated, with more people dropping out due to side effects.
Psychological therapies such as CBT, mindfulness, and psychoeducation showed some benefits, but mainly according to clinician ratings—not necessarily from the patients themselves. Neurostimulation techniques like transcranial direct current stimulation also showed some improvements, but only in limited contexts and with small sample sizes. Interestingly, none of the treatments—medication or otherwise—made a clear impact on long-term quality of life or emotional regulation.
Conclusion
So, what does this mean for people navigating ADHD in adulthood? Stimulant medications remain the most effective treatment for managing ADHD symptoms day-to-day but nonstimulant medication are not far behind, which is good given the problems we’ve had with stimulant shortages. This study also supports structured psychotherapy as a viable treatment option, especially when used in conjunction with medication.
The study emphasizes the importance of ongoing, long-term research and the need for treatment plans that are tailored to the individual ADHD patient– Managing adult ADHD effectively calls for flexible, patient-centered care.
------
Struggling with side effects or not seeing improvement in your day-to-day life? Dive into a step-by-step journey that starts with the basics of screening and diagnosis, detailing the clinical criteria healthcare professionals use so you can be certain you receive an accurate evaluation. This isn’t just another ADHD guide—it’s your toolkit for getting the care you deserve. This is the kind of care that doesn’t just patch up symptoms but helps you unlock your potential and build the life you want. Whether you’ve just been diagnosed or you’ve been living with ADHD for years, this booklet is here to empower you to take control of your healthcare journey.
Proceeds from the sale of this book are used to support www.ADHDevidence.org.
_logo%201.svg)
