August 19, 2021

Association found between ADHD risk genes involved in dopamine signaling and reduced estimated life expectancy

Behavioral disinhibition is a trait associated with both ADHD and several genes that affect dopamine signaling. A new study by three American medical researchers set out to examine how these ADHD risk genes - DRD4 (dopamine 4 receptor density), DAT1 (dopamine 1 transporter), and DBH(dopamine beta-hydroxylase) - affect estimated life expectancy in young adulthood.

The method used was a longitudinal study of 131 hyperactive children and 71 matched controls through early adulthood. The original evaluations were done in 1979-1980, when both groups were children in the 4 to 12 age range. They were reevaluated in1987-1988 as adolescents aged 12 to 20. The next follow-up was in 1992-1996 in early adulthood, aged 19 to 25. The final follow-up was in 1998-2004, for adults aged 24 to 32. All agreed to physical examinations that formed the basis for calculating estimated life expectancy using actuarial tables that factor in the effects of smoking, body mass index, alcohol, and other risk factors of on expected longevity. Participants also provided blood samples that enabled gene typing.

For the DAT1 gene, participants who had the homozygous-repeat allele (9/9) had a five-year reduction in estimated life expectancy relative to those with the ten-repeat allele (10/10). Those with the intermediate (9/10) configuration had a three-year reduction in estimated life expectancy.

For the DBH Taq1 gene, those with a heterozygous (A1/A2) combination had almost a three-year reduction in estimated life expectancy relative to those with homozygous (A1/A1 or A2/A2)configurations.

For DRD4, on the other hand, no significant differences were found in estimated life expectancy.

In a related study, several background traits were found to be significantly predictive of variance estimated life expectancy. The largest of these was behavioral disinhibition, followed by verbal IQ, self-rated hostility, and a nonverbal fluency test. But no significant differences were found between any of the gene polymorphisms on any of these four measures, indicating that the present gene associations were independent of the background traits.

The researchers next sought to determine which variables used in the estimated life expectancy calculations were associated with the two significant genes. For DBH, one variable stood out. Those with the A1/A2 heterozygous pairings had almost twice the alcohol consumption of those with homozygous pairings (p = 0.023).

For DAT1, two variables stood out. Overall, the 9/9 pairings smoked two and a half times as much as the 10/10pairings, with the 9/10 pairings midway between the extremes (p = 0.036). They were also 73 percent more likely to be smokers relative to the 10/10 pairings, and 61 percent more likely relative to the 9/10 pairings. They also had significantly less education than the 10/10 pairings, with the 9/10 pairings again being intermediate (p = 0.027).

An obvious limitation of the study was its small sample size. The authors cautioned, our findings should be considered quite preliminary and in need of much greater research before being given much weight in the literature or public policy.

"With these limitations in mind, they concluded, the present study demonstrated that two ADHD risk genes (DB Hand DAT1) independently contributed to a reduction in ELE [estimated life expectancy] beyond the second-order variables of behavioral disinhibition, IQ, hostility, and nonverbal fluency that contributed in the related study to variation in ELE. The gene polymorphisms seemed to be influencing ELE through their affiliation with first-order or more proximal factors related to ELE such as education, smoking, alcohol use, and possibly exercise."

Russell A. Barkley, Karen Müller Smith, and Mariellen Fischer, ADHD risk genes involved in dopamine signaling and metabolism are associated with reduced estimated life expectancy at young adult follow-up in hyperactive and control children, American Journal of Medical Genetics(2019), DOI:10.1002/aiming.b.32711.

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Exploring the Impact of ADHD Treatment on Empathy and Narcissism

A recent study published in Alpha Psychiatry sheds light on the connection between ADHD, empathy, and narcissistic traits. Researchers aimed to evaluate how pharmacological treatments—specifically psychostimulants—affect empathy deficits and pathological narcissism in adults with ADHD. These findings could have important implications for enhancing treatment outcomes and improving social functioning.

Study Overview
The study involved 75 adult ADHD patients who were treated with either methylphenidate or atomoxetine. Researchers assessed levels of narcissistic traits and empathy using validated tools such as the Pathological Narcissism Inventory (PNI) and the Empathy Quotient (EQ). Measurements were taken before treatment and after three months of therapy.

Key Findings

  • Narcissistic Traits: Patients showed a significant reduction in grandiosity and vulnerability scores, with total PNI scores decreasing after treatment.
  • Empathy Levels: Empathy improved significantly, as reflected by higher post-treatment EQ scores.
  • Overall Impact: These changes suggest that psychostimulant treatment positively influences brain circuits related to empathy and narcissistic tendencies, potentially leading to better interpersonal relationships.

Why It Matters
Adults with ADHD often struggle with social interactions, partly due to empathy deficits and personality traits like narcissism. By addressing these challenges through psychostimulant treatment, patients may experience better social and emotional well-being. This study underscores the importance of viewing ADHD treatment as not just a way to manage symptoms but also a means to improve overall quality of life.Takeaway
Effective ADHD treatment goes beyond managing attention and hyperactivity. By improving empathy and reducing narcissistic traits, psychostimulants can foster healthier relationships and enhance social functioning. This research highlights the need for comprehensive care that considers the broader psychological and interpersonal effects of ADHD.

February 4, 2025

Meta-analysis Suggests Music Training May Be a Useful Tool for Inhibition Control

According to Fosco et al. (2019), “Inhibitory control has long been considered a central neurocognitive process in ADHD, with ADHD groups typically showing medium-sized impairments relative to their typically-developing peers on common inhibition paradigms.” 

Learning to play a musical instrument requires effective coordination of physical movements and sound signals to produce music. Musical training involves repetitive practice, perfecting connections between perceptions, muscular actions, and cognition. 

Noting that listening to music activates the brain’s reward circuits in both children and adults, that “Being internally motivated during learning experiences increases learning capacity and efficiency, and this greater engagement is reflected in increased electrical brain activity following musical training,” and that “Training music in a social environment increases positive feelings of bonding through shared emotions and group synchrony,” a Montreal-based research team carried out a systematic review and meta-analysis of the peer-reviewed medical literature from 1980 to 2023 to learn what effect music training might have on inhibition control. 

Outcomes:

The team found eight randomized controlled trials (RCTs) and 14 other longitudinal studies that met search criteria, including: 

  • Music training was with neurotypical children and adolescents 
  • The experimental group was trained using music alone 
  • Studies were longitudinal, with either active or passive controls 
  • Studies included a performance-based inhibition control measure as an outcome 

Meta-analysis of all 22 longitudinal studies with a combined total of 1,734 participants yielded a small-to-medium effect size improvement in inhibitory control. Variation (heterogeneity) in outcomes between individual studies was small, and there was no sign of publication bias. Restricting the analysis to the eight RCTs with a combined total of 641 participants, however, yielded a medium-to-large effect size improvement, with negligible heterogeneity, meaning the outcome was consistent across RCTs. 

The Take-Away: The team concluded, “Music training plays a privileged role compared to other activities (sports, visual arts, drama) in improving children’s executive functioning, with a particular effect on inhibition control.”   I cannot, however, recommend this as a therapy for ADHD until RCTs show it reduces symptoms of ADHD and/or real world impairments associated with the disorder.

February 3, 2025

Population Study Finds No ADHD- or ASD- Related Benefits From Eating Organic Food During Pregnancy

Norwegian Nationwide Population Study Finds No ADHD- or ASD- Related Benefits From Eating Organic Food During Pregnancy

Background:

Organic farming aims to protect biodiversity, promote animal welfare, and avoid using pesticides and fertilizers made from petrochemicals. Some pesticides are designed to target insects’ nervous systems but can also affect brain development and health in larger animals, including humans.

Many people believe organic food is healthier than conventionally produced food, which might be true for certain foods and health factors. But does eating organic food during pregnancy impact the chances of a child developing ADHD or autism spectrum disorder (ASD)?

In Norway, researchers can use detailed national health records to study these connections on a population-wide level, thanks to the country’s single-payer healthcare system and national registries.

Method:

The Norwegian Mother, Father, and Child Cohort Study (MoBa) invites parents to participate voluntarily and has a 41% participation rate. The study includes:

  • 114,500 children
  • 95,200 mothers
  • 75,200 fathers

For this research, a team tracked 40,707 mother-child pairs from children born between 2002 and 2009. They used questionnaires to measure how much organic food mothers consumed during pregnancy. ADHD and ASD symptoms in children were assessed using validated rating scales.

The final analysis included:

  • 40,586 pairs for ADHD symptoms
  • 40,117 pairs for ASD symptoms

The researchers adjusted for factors like maternal age, education, previous pregnancies, BMI before pregnancy, smoking and alcohol use during pregnancy, birth year and season, and the child’s sex.

Key Findings:
  • There was a weak connection between higher organic food consumption and fewer ADHD symptoms in children. However, this link disappeared when maternal ADHD symptoms were considered (31,411 pairs) or when the analysis was limited to siblings (5,534 pairs).
  • Similarly, weak associations between organic food and fewer ASD symptoms disappeared when focusing on siblings (4,367 pairs).
Conclusion:

The researchers concluded that eating organic food during pregnancy has no meaningful effect on the likelihood of a child developing ADHD or ASD. They stated, “The results do not indicate any clinically significant protective or harmful effects of eating organic food during pregnancy on symptoms of ADHD and ASD in the offspring. Based on these findings, we do not recommend any specific advice regarding intake of organic food during pregnancy.”

January 27, 2025