January 20, 2022

Large longitudinal cohort study finds association between nitric oxide in air pollution and ADHD (hyperactivity)

Taiwan's National Birth Registration database tracks every birth. Using all entries from 2005, random sampling was used to create the Taiwan Birth Cohort Study of 24,200 mother-infant pairs, which were geographically distributed and represented 12 percent of all births.

As this was an eight-year longitudinal study, there were dropouts, and 17,256 pairs completed the study. After excluding cases with fetal distress, smoking or alcohol use during pregnancy, and missing information on covariates, the final study population was 16,376.

Participants' addresses during gestation were geocoded to the township level, and local air pollution data was retrieved for the years 2004 to 2006 from air quality monitoring stations administered by Taiwan's Environmental Protection Administration. Every hour, each station records levels of nitric oxide (NO), nitrogen dioxide (NO2), nitrogen oxides (NOx), sulfur dioxide (SO2), carbon monoxide (CO), and particulate matter of diameter 10 μm or less (PM10).

The Taiwanese research team addressed several potential confounding factors: sex, maternal age, delivery method (cesarean section or not), birth in summer (June-August), urban or rural residence, and annual household income.

Because ADHD is primarily observable as hyperactivity rather than inattention among young children, the team focused on relating symptoms of hyperactivity to levels of air pollutants.

After adjusting for covariates, the team found no significant association between PM10 and SO2 levels and hyperactivity disorder. Nitrogen oxide levels, on the other hand, were associated with more than 25 percent higher odds of hyperactivity.

Breaking that down further, they found no significant association with NO2, and that the 25 percent higher odds were exclusive with nitric oxide (NO), a pollutant emitted by internal combustion engines in cars, trucks, and busses. NO is a free radical, meaning it has an unpaired electron that can damage the body because of its strong chemical reactivity.

The authors noted, "Our study has some limitations. First, hyperactivity was diagnosed based on a parent-reported physician or specialist diagnosis. Although we did not inquire which specialists made these diagnoses, they must have been a pediatrician, psychiatrist, or special education teacher. ... Second, the calculated exposure to ambient air pollutants was not an accurate personal exposure because it did not take indoor air pollutant levels and time-activity patterns into consideration. Applying personal environmental monitoring in such a large sample is impractical, especially when the subjects are pregnant."

Nevertheless, they emphasized, "this is the first study attempting to discover which component of NOx is more critical to the development of hyperactivity in offspring."

Ping Shih, Ching-Chun Huang, Shih-Chun Pan, Tung-Luang Chiang Yue Leon Guo, "Hyperactivity disorder in children related to traffic-based air pollution during pregnancy," Environmental Research(2020),188: 109588, https://doi.org/10.1016/j.envres.2020.109588.

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News Tuesday: Fidgeting and ADHD

A recent study delved into the connection between fidgeting and cognitive performance in adults with Attention-Deficit/Hyperactivity Disorder. Recognizing that hyperactivity often manifests as fidgeting, the researchers sought to understand its role in attention and performance during cognitively demanding tasks. They designed a framework to quantify meaningful fidgeting variables using actigraphy devices.

(Note: Actigraphy is a non-invasive method of monitoring human rest/activity cycles. It involves the use of a small, wearable device called an actigraph or actimetry sensor, typically worn on the wrist, similar to a watch. The actigraph records movement data over extended periods, often days to weeks, to track sleep patterns, activity levels, and circadian rhythms. In this study, actigraphy devices were used to measure fidgeting by recording the participants' movements continuously during the cognitive task. This data provided objective, quantitative measures of fidgeting, allowing the researchers to analyze its relationship with attention and task performance.)

The study involved 70 adult participants aged 18-50, all diagnosed with ADHD. Participants underwent a thorough screening process, including clinical interviews and ADHD symptom ratings. The analysis revealed that fidgeting increased during correct trials, particularly in participants with consistent reaction times, suggesting that fidgeting helps sustain attention. Interestingly, fidgeting patterns varied between early and later trials, further highlighting its role in maintaining focus over time.

Additionally, a correlation analysis validated the relevance of the newly defined fidget variables with ADHD symptom severity. This finding suggests that fidgeting may act as a compensatory mechanism for individuals with ADHD, aiding in their ability to maintain attention during tasks requiring cognitive control.

This study provides valuable insights into the role of fidgeting in adults with ADHD, suggesting that it may help sustain attention during challenging cognitive tasks. By introducing and validating new fidget variables, the researchers hope to standardize future quantitative research in this area. Understanding the compensatory role of fidgeting can lead to better management strategies for ADHD, emphasizing the potential benefits of movement for maintaining focus.

July 16, 2024

Identifying Autistic-Like Symptoms in Children with ADHD

NEWS TUESDAY: Identifying Autistic-Like Symptoms in Children with ADHD

A recent study investigated the presence of autistic-like symptoms in children diagnosed with Attention Deficit/Hyperactivity Disorder (ADHD). Given the overlapping social difficulties in both ADHD and Autism Spectrum Disorder (ASD), distinguishing between the two disorders can be challenging. This study aims to pinpoint specific patterns of autistic symptoms in children with ADHD, comparing them to those with ASD using the Autism Diagnostic Observation Schedule, 2nd edition (ADOS-2).

The research involved 43 school-age children divided into two groups:

  • ADHD Group (25 children): Initially referred for ASD symptoms but later diagnosed with ADHD.
  • ASD Group (18 children): Children diagnosed with ASD.

Researchers used ADOS-2 to evaluate differences in communication deficits, social interaction challenges, and repetitive behaviors between the two groups. The study also compared IQ, age, ADOS-2 domain scores, and externalizing/internalizing problems.

Key Findings:

  • Significant differences were found between the ADHD and ASD groups in ADOS-2 domain scores, including Social Affect, Restricted and Repetitive Behavior, and Total Score.
  • On an individual item level, children with ADHD displayed similar atypical behaviors as those with ASD in social-communication areas such as "Pointing" and "Gestures".
  • Both groups showed comparable frequencies in behaviors like "Stereotyped/idiosyncratic words or phrases", "Mannerisms", and "Repetitive interests and behaviors".

The study highlights the importance of identifying transdiagnostic domains that overlap between ADHD and ASD. The transdiagnostic domain refers to a set of symptoms or behaviors that are common across multiple diagnostic categories rather than being specific to just one. Identifying these domains in mental health practice and in psychological research is crucial to understanding, properly diagnosing, and treating conditions with overlapping features. This understanding could pave the way for tailored treatments addressing the specific needs of children with ADHD, particularly those exhibiting autistic-like symptoms.

July 9, 2024

Non-stimulant Medications for Adults with ADHD: An Overview

NEW STUDY: Non-stimulant Medications for Adults with ADHD: An Overview

Attention-Deficit/Hyperactivity Disorder (ADHD) in adults is commonly treated with stimulant medications such as methylphenidate and amphetamines. However, not all patients respond well to these stimulants or tolerate them effectively. For such cases, non-stimulant medications provide an alternative treatment approach.

Recent research by Brancati et al. reviews the efficacy and safety of non-stimulant medications for adult ADHD. Atomoxetine, a well-studied non-stimulant, has shown significant effectiveness in treating ADHD symptoms in adults. The review highlights the importance of considering dosage, treatment duration, safety, and the presence of psychiatric comorbidities when prescribing atomoxetine.

Additionally, certain antidepressants, including tricyclic compounds, bupropion, and viloxazine, which possess noradrenergic or dopaminergic properties, have demonstrated efficacy in managing adult ADHD. Antihypertensive medications, especially guanfacine, have also been found effective. Other medications like memantine, metadoxine, and mood stabilizers show promise, whereas treatments like galantamine, antipsychotics, and cannabinoids have not yielded positive results.

The expert opinion section of the review emphasizes that while clinical guidelines primarily recommend atomoxetine as a second-line treatment, several other non-stimulant options can be utilized to tailor treatments based on individual patient needs and comorbid conditions. Despite these advancements, the authors call for further research to develop and refine more personalized treatment strategies for adults with ADHD.

This review underscores the growing landscape of non-stimulant treatment options, offering hope for more personalized and effective management of ADHD in adults.

June 25, 2024