March 5, 2022
Persons with ADHD have known to have high rates of psychiatric comorbidities. There is also growing evidence of somatic (non-psychiatric) comorbid disorders among youths with ADHD, such as metabolic syndrome (which can lead to type 2 diabetes) and chronic inflammation (such as asthma and allergic rhinitis). Much less is known, however, about comorbid conditions in adults with ADHD.
An international team of researchers looked for indicators of comorbid conditions in a nationwide cohort study using Swedish national registers. The target population was Swedish residents between the ages of 18 and 64 in 2013 and more specifically those who had been prescribed ADHD medication. They identified over 41,000 individuals who met these criteria, including over twenty thousand young adults aged 18-29 years, over sixteen thousand middle-aged adults aged 30-49 years, and over four thousand older adults aged 50-64. The remainder of the overall cohort were used as controls.
Young adults receiving ADHD medications were four times as likely to also be receiving somatic medications, and older adults were seven times as likely. The highest rate of co-medication -roughly five times more frequent than among controls - was for respiratory system medications. The second most common was for alimentary tract and metabolic system medications, with odds over four times higher than for controls. Cardiovascular system medications were the next most common, with odds among young adults receiving ADHD medications over four times those of controls, though reducing with age to being twice as common in older adults with ADHD. Patterns were similar among men and women.
Adults receiving ADHD medications were far more likely to also be receiving other psychotropic medications. Middle-aged adults were 21 times as likely to be dispensed such medications as controls, older adults eighteen times more likely, and younger adults fifteen times more likely.
For young adults prescribed ADHD medications, the most prevalent co-prescriptions were for addictive disorders, which were dispensed at over 26 times the rate for controls. For middle-aged and older adults, on the other hand, the most prevalent co-prescriptions were for antipsychotics, which were likewise dispensed at over 26 times the rate for controls. Results remained consistent for individuals who had an ADHD diagnosis in addition to an ADHD prescription.
In addition, individuals receiving ADHD medications were also on average taking more types of prescriptions, rising from 2.5 classes of medications at age 18 to five classes at age 64. For controls, the equivalent numbers were 0.9 types of medications at age 18, rising to 2.7 at age 64.
Looking at specific somatic medications prescribed, those for respiratory conditions were ones typically prescribed for asthma and allergic reactions, reinforcing a previously known association. Insulin preparations also had high rates of co-prescription, again further confirming the known association with obesity and diabetes.
On the other hand, the most commonly dispensed alimentary tract and metabolic system medications included proton pump inhibitors, typically prescribed for gastric/duodenal ulcers and gastroesophageal reflux disease. Sodium fluoride, prescribed to prevent dental caries, was also prominent. Neither of these is an established association and warrants further exploration.
Turning to psychotropic medications, the most frequent prescriptions were with drugs used to treat addictive disorders and with antipsychotics. Rates of opioid co-prescription were also notably high, a source of concern given the higher proclivity of persons with ADHD to substance use disorders.
Le Zhang, AndreasReif, Ebba Du Rietz, Tyra Lagerberg, Agnieszka Butwicka, Brian M. D'Onofrio, Kristina Johnell, Nancy L. Pedersen, Henrik Larsson, and Zheng Chang, "Comedicationand Polypharmacy With ADHD Medications in Adults: A Swedish Nationwide Study," Journal of Attention Disorders (2020),https://doi.org/10.1177/1087054720923725.
Background
ADHD (Attention-Deficit/Hyperactivity Disorder) is one of the most studied neurodevelopmental conditions, with many clinical trials evaluating the effectiveness and safety of various medications. These trials, known as randomized controlled trials (RCTs), are considered the gold standard for assessing treatments. However, strict eligibility criteria often exclude many real-world patients, raising questions about whether the findings from these trials apply to everyday clinical settings.
Our latest study sheds light on this issue, revealing just how many individuals with ADHD might be excluded from RCTs and the impact this exclusion has on their treatment outcomes.
Method
Researchers used Swedish national registries to analyze data from 189,699 individuals diagnosed with ADHD who started medication between 2007 and 2019. They applied exclusion criteria from 164 international RCTs to identify who would have been considered ineligible for these trials in order to determine the proportion of individuals with ADHD who would not meet the eligibility criteria for RCTs.
Key Findings
Many Patients Are Ineligible for Clinical Trials:
Ineligible Patients Face Unique Challenges:
Higher Risk of Adverse Outcomes:
What This Means
These findings highlight a major gap between the controlled environments of clinical trials and the realities faced by individuals with ADHD in everyday life. While RCTs provide valuable insights, their restrictive criteria often exclude patients with more complex health profiles or co-existing conditions. This limits the generalisability of trial results, meaning that treatment guidelines based solely on RCTs may not fully address the needs of all patients.
Conclusion
This study demonstrated that a significant proportion of individuals with ADHD, particularly adults, do not meet the eligibility criteria for standard RCTs. These results emphasize the importance of bridging the gap between research settings and real-world applications. By recognizing and addressing the limitations of RCTs, we can work towards more equitable and effective ADHD treatment strategies for everyone.
Background:
Our understanding of Attention-deficit/hyperactivity disorder (ADHD) has grown and evolved considerably since it first appeared in the DSM-II as “Hyperkinetic Reaction of Childhood.” This study aimed to find the disorder’s placement within the modern psychopathology classification systems like the Hierarchical Taxonomy Of Psychopathology (HiTOP).
The HiTOP model aims to address limitations of traditional classification systems for mental illness, such as the DSM-5 and ICD-10, by organizing psychopathology according to evidence from research on observable patterns of mental health problems.. Is ADHD best categorized under externalizing conditions, neurodevelopmental disorders, or something else entirely? A recent study by Zheyue Peng, Kasey Stanton, Beatriz Dominguez-Alvarez, and Ashley L. Watts takes a closer look at this question using a symptom-focused approach.
The Study:
Traditionally, ADHD has been associated with externalizing behaviors, such as impulsivity and hyperactivity, or with neurodevelopmental traits, like cognitive delays. However, this study challenges the idea of placing ADHD into a single category. Instead, it maps ADHD symptoms across three major psychopathology spectra: externalizing, neurodevelopmental, and internalizing.
The findings reveal that ADHD symptoms don’t fit neatly into one box. For example, symptoms like impulsivity, poor school performance, and low perseverance were strongly associated with externalizing behaviors. On the other hand, cognitive disengagement (e.g., daydreaming, blank staring) and immaturity were closely linked to neurodevelopmental challenges. Interestingly, cognitive disengagement also showed ties to internalizing symptoms, such as anxiety or depression.
This research underscores the complexity of ADHD. Rather than treating ADHD as a single, unitary construct, the study advocates for a symptom-based approach to better understand and treat individuals. By acknowledging that ADHD symptoms relate to multiple psychopathology spectra, clinicians and researchers can move toward more nuanced classification systems and targeted interventions.
Conclusion:
Ultimately, this study highlights the need for modern systems to move beyond rigid categories and adopt a more flexible, symptom-focused framework for understanding ADHD’s place in psychopathology.
The Background:
Caffeine and its primary breakdown compounds – paraxanthine, theophylline, and theobromine (also the primary alkaloid in chocolate) – readily cross the placenta and tend to linger due to the underdevelopment of fetal caffeine metabolizing enzymes.
Could accumulating caffeine metabolites harm the developing fetal brain? Studies to date have come to contradictory conclusions, some finding an association, others finding none.
Norway has a national single-payer health insurance system with a national health registry comprehensively tracking virtually all residents.
The Methods:
An international study team used Norways’s registry, and its Mother, Father, and Child Cohort Study (MoBa) to explore the relationship between maternal and paternal coffee consumption and offspring neurodevelopmental difficulties (ND), including symptoms of ADHD as determined from validated rating scales, using 58,964 mother-child pairs and 22,576 father-child pairs, covering the decade 1999-2008.
Unadjusted results indicated a strong association between maternal coffee consumption before and during pregnancy with offspring ADHD, but none with paternal coffee consumption. Superficially, that might seem like compelling evidence.
Yet after adjusting for education, income, smoking, and alcohol, “previously significant effects attenuated towards zero and some associations switched from being positive to negative.”
Then, after further adjusting for genetic confounding, ADHD symptoms at 1.5 years, 3 years, 5 years (on both of two different rating scales), and 8 years (including separate measures of inattention and hyperactivity symptoms) all became indistinguishable between offspring from mothers consuming coffee during pregnancy and offspring of mothers abstaining from coffee during pregnancy.
Conclusion:
The team concluded, “This study applied several conventional and genetic epidemiological approaches to investigate the potential relationship between maternal coffee consumption during pregnancy and offspring NDs [neurodevelopmental difficulties]. When considering the results of the conventional and genetic epidemiological analyses, as well as the broader literature, we conclude that there is little evidence that maternal coffee consumption during pregnancy is strongly causally related to offspring NDs.”
More specifically, the team found no evidence of any causal relationship with offspring ADHD.
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