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Background:

“Junk food” is a shorthand for highly processed foods and beverages with low nutritional value and dietary fiber that are typically high in added sugars, starches, and additives intended to boost flavor, color, texture, and shelf life. 

Previous studies examining such an association have yielded contradictory or inconclusive results. 

Method:

An Iranian research team therefore conducted a systematic search of the peer-reviewed medical literature to run a meta-analysis of data from studies published to date. 

Meta-analysis of nine studies, with a combined total of over 58,000 persons, found that children and adolescents who consumed more junk foods were about 25% more likely to exhibit ADHD symptoms. Restricting this to the seven studies rated good or high quality (7+ out of 10 on the Newcastle–Ottawa Quality Assessment Scale) produced the same exact outcome.  

The result was consistent across individual studies, with low heterogeneity. There was no sign of publication bias. 

Breaking this down by subtype of junk food: 

• Combining six studies with over 52,000 total participants, sugary beverages including soft drinks were associated with the same 25% increase in ADHD symptoms. Heterogeneity was moderate. 

• Combining three studies with over 1,600 total participants, solid sweets and candies were associated with a greater than one-third increase in ADHD symptoms. There was no variation in outcome among the three studies. 

• Combining three studies with over 22,000 total participants, other heavily processed foods were associated with a 17% increase in ADHD symptoms. Again, there was no variation in outcome among the three studies. 

The team used data adjusted for confounders: “We used … adjusted OR [odds ratios] for the meta-analysis.” 

This outcome, while suggestive, should be interpreted cautiously due to limitations: 

• ADHD symptoms were rated by parents or caregivers using standardized questionnaires. ADHD diagnoses by qualified medical professionals are the gold standard, and were not used. 

• Junk food consumption was likewise estimated by parents or caregivers through answers to questionnaires. There was no direct measurement of consumption. Answers were categorical, making it impossible to look for dose-response relationships. 

• Even if the association holds with further study, it is unclear whether impulsivity associated with ADHD leads to greater consumption of junk foods, or junk food consumption somehow harms development of the nervous system, or the relationship is due to unmeasured confounding by other variables.   

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Conclusion:

The team concluded, “This meta-analysis of observational studies adds strong evidence linking the consumption of junk foods, particularly, sweetened beverages/soft drinks and sweets/candies, with ADHD symptoms in children and adolescents. However, the study did not evaluate the causality of the relationship. So, to identify causality and the dose–response effects of junk food consumption on the development of ADHD, further studies are warranted.” 

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A research team based in London (U.K.) has just released the first meta-analysis to explore whether young people with ADHD experience greater loneliness compared to young people without ADHD.  

There has been a lot of research into social-emotional functioning in ADHD focusing on social networks and peer functioning problems, with little inquiry into young people’s experience of and satisfaction with their relationships.  

The team noted, “This is an important distinction as loneliness, or perceived social isolation, is the subjective feeling of distress due to a perceived deficit in the quantity and quality of one’s social relationships. An individual may be objectively socially isolated but may not have a negative perception of their relationships and equally, someone may find their social relationships lacking despite having a large social network … As loneliness and social isolation (e.g., number of friends or size of social network) have been found to be weakly correlated, it is important to capture the loneliness experience of the young person rather than relying on just the objective measures of social isolation.” 

Loneliness is a public health concern, as it predicts increases in depression, anxiety, self-harm, and suicidal ideation. 

The team performed a systematic search of the peer-reviewed medical literature to identify quantitative studies that compared loneliness among young people under 25 diagnosed with ADHD with non-ADHD matched controls. The search excluded studies in which participants had intellectual disabilities and/or other neurodevelopmental conditions such as autism spectrum disorder. 

Meta-analysis of 15 studies with a combined 6,281 participants found that young people with ADHD experienced greater loneliness than their non-ADHD peers with a small-to-medium effect size. There was no sign of publication bias, but very high variation (heterogeneity) in outcomes across the studies.  

Removing one small outlier study, the remaining 14 studies with 6,099 participants brought heterogeneity down to moderate levels, and yielded a medium effect size increase in perceived loneliness among young people with ADHD.  

Conclusion: 

“The findings in this study highlight the importance of understanding loneliness in this population as young people with ADHD report significantly higher levels of loneliness compared to their non-ADHD peers, and loneliness in young people with ADHD is associated with a range of mental health difficulties,” the researchers stated. “More resources should be focused on loneliness as a separate construct from social isolation and peer difficulties.” 

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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.

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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.

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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.

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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.

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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.

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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.

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.”

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Background:

Infertility affects about one in six couples worldwide. To address this, medical experts have developed Assisted Reproductive Technologies (ART), including In Vitro Fertilization (IVF) with or without Intra-Cytoplasmic Sperm Injection (ICSI).

Some research suggests that children conceived through ART might have higher rates of intellectual disabilities, cerebral palsy, cancer, and neurological issues compared to children conceived naturally. However, studies looking at a possible link between ART and ADHD have produced mixed and conflicting results.

Until now, there hasn’t been a meta-analysis examining the connection between ART and ADHD. A South Korean research team has conducted the first systematic review and meta-analysis on this topic. Their final analysis included eight studies with a total of over ten million participants, comprising six cohort studies and two cross-sectional studies.

Method:

The research focused on two types of studies:

1. Cohort Studies: These follow two groups (one exposed to ART and one not exposed) over time to see if a specific outcome, like ADHD, occurs.
2. Cross-Sectional Studies: These compare the prevalence of ADHD at a single point in time between those exposed to ART and those who weren’t.

Both types of studies are observational, meaning they don’t involve controlled experiments and can be influenced by confounding factors.  So they can document interesting associations, not causality.  The studie were mostly large-scale national studies and used clinical ADHD diagnoses.

Key Findings:

• Cohort Studies: Meta-analysis of six cohort studies, involving nearly 8 million participants, found no link between ART and ADHD. However, there was high variability (heterogeneity) in the results from individual studies.
• Cross-Sectional Studies: Meta-analysis of two cross-sectional studies, covering over 2.3 million participants, also found no link between ART and ADHD. Heterogeneity was moderate.
• Adjustment for Confounding: A separate analysis of three studies that adjusted for confounding factors (like socioeconomic status or parental health) involved more than 7.5 million participants. It found a very small association, with ART-conceived children being 8% more likely to develop ADHD. There was no variability among these studies.

Conclusion:

The researchers concluded that while there may be a small association between ART and ADHD, the effect is minimal, and the results are influenced by differences in study designs. They advised interpreting these findings with caution, noting, “The limited effect size and inherent heterogeneity underscore the need for cautious interpretation.”

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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:

• Over half (53%) of the study population would have been ineligible for ADHD medication trials.
• Adults were most likely to be excluded (74%), followed by adolescents (35%) and children (21%).

Ineligible Patients Face Unique Challenges:

• Treatment Switching: Ineligible individuals were more likely to switch medications within the first year (14% higher likelihood compared to eligible patients).
• Medication Discontinuation: They were slightly less likely to stop taking their medication during the first year.

Higher Risk of Adverse Outcomes:

• Ineligible patients experienced significantly higher rates of psychiatric hospitalizations and health issues such as depression, anxiety, and substance use disorders. For instance:some text
  • Psychiatric hospitalizations: Nearly 10 times more likely.
  • Specialist visits for substance use disorders: About 15 times more likely.
  • Anxiety-related visits: Over 11 times more likely.

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.

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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.

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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.

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Background:

Exposure to heavy metals like lead, arsenic, mercury, cadmium, and manganese is known to harm developing nervous systems. However, past studies on whether heavy metals specifically increase the risk of ADHD have shown mixed results.

A research team from China (Gu et al., 2024) reviewed medical studies and conducted meta-analyses to better understand this issue.

Methods:

The team included studies on children and teens, focusing on cohort studies, case-control studies, and cross-sectional studies. They only used articles written in English and required validated biomonitoring (like blood tests) to measure heavy metal exposure. ADHD diagnoses had to come from clinical evaluations.

To be included, studies had to report effect sizes such as odds ratios and relative risks with confidence intervals. The team focused on comparisons between groups with high, low, or no exposure, which made it harder to analyze dose-response relationships.

They also evaluated the quality of each study. All cohort studies were rated high-quality. Of the 15 case-control studies, 6 were high-quality, and 9 were moderate-quality. Among cross-sectional studies, only 2 were high-quality, and the rest were moderate-quality.

Key Findings:

1. Lead Exposure and ADHD:some text
   • A meta-analysis of 22 studies with over 20,000 participants found that early exposure to lead was linked to about twice the odds of an ADHD diagnosis compared to unexposed children.
   • However, results varied widely among studies, and signs of publication bias were detected. After adjusting for this bias, the increased odds dropped to about 50%.
   • A dose-response relationship was found:some text
     • Blood lead levels of 2.5 µg/dL increased ADHD risk by 1.8 times.
     • Levels of 5 µg/dL increased the risk 2.5 times.
     • Levels of 7.5 µg/dL increased the risk 2.75 times.
     • Levels of 10 µg/dL tripled the risk.
2. Other Metals:some text
   • No significant links were found between ADHD and exposure to arsenic, mercury, cadmium, or manganese. Fewer studies were available for these metals, and participant numbers were much smaller:some text
     • Arsenic exposure: 25% higher odds of ADHD (4 studies, 3,116 participants).
     • Mercury exposure: 25% higher odds (6 studies, 2,916 participants).
     • Cadmium exposure: 25% higher odds (5 studies, 2,419 participants).
     • Manganese exposure: 45% higher odds (6 studies, 1,664 participants).
3. Austrian Study: An Austrian team (Rosenauer et al., 2024) also conducted a meta-analysis on lead exposure and ADHD. They included 14 studies with over 7,600 participants and found:some text
   • Lead exposure increased the odds of ADHD by about 25%.
   • Studies focusing on higher lead levels found a 43% increased risk, supporting a dose-response relationship.
   • Study results were consistent, with no signs of publication bias.

Conclusion:

There was no evidence linking ADHD to other heavy metals like arsenic, mercury, cadmium, or manganese.  Both meta-analyses suggest that lead exposure is associated with the risk for ADHD.  However, because these studies cannot rule out other explanations, one cannot conclude that lead exposure causes ADHD.  For example, other work shows that people with ADHD are likely to have lower incomes than those without ADHD.  

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