November 21, 2025

Oppositional Defiant Disorder, Autism, and ADHD: New Research Examines the Connection

Oppositional Defiant Disorder (ODD)—a pattern of chronic irritability, anger, arguing, or defiance—is one of the most challenging behavioral conditions families and clinicians face. 

A new study involving 2,400 children ages 3–17 offers one of the clearest pictures yet. Using parent-reported data from the Pediatric Behavior Scale, researchers compared how often ODD appears in Autism spectrum disorder (ASD), ADHD-Combined presentation (ADHD-C), ADHD-Inattentive presentation (ADHD-I), and those with both ASD and ADHD.

Results

ADHD-Combined + ODD: The Highest-Risk Group

Children with ADHD-Combined presentation show both hyperactivity/impulsivity and inattention.  They had the highest ODD rates of any single diagnosis: 53% of kids with ADHD-Combined met criteria for ODD.

But when autism was added to ADHD-Combined, the prevalence jumped to 62%. This group also had the highest overall ODD scores, suggesting more severe or more impairing symptoms. 

This synergy matters: while autism alone increases ODD risk, the presence of ADHD-Combined is what pushes prevalence into the majority range. Other groups showed lower, but still significant, rates of ODD:

  • Autism + ADHD-Inattentive: 28%
  • Autism Only: 24%
  • ADHD-Inattentive Only: 14%

These findings echo what clinicians often see: children with inattentive ADHD, while struggling significantly with attention and learning, tend to show fewer behavioral conflict patterns than those with hyperactive/impulsive symptoms.

It is important to note that ODD is considered to have two main components. Across all diagnostic groups, ODD consistently broke down into these two components: either Irritable/Angry (emotion-based) or Oppositional/Defiant (behavior-based). But the balance between these components differed depending on diagnosis. Notably, Autism + ADHD-Combined showed higher levels of the irritable/angry component than ADHD-Combined alone. The oppositional/defiant component did not differ much between groups. This suggests that autism elevates the emotional side of ODD more than the behavioral side, which is important for clinicians to note before tailoring interventions.

Understanding ADHD , ASD, & Comorbidity:

The study notes that autism, ADHD, and ODD often cluster together, with 55–90% comorbidity in some combinations.

As the authors explain, The high co-occurrence of ADHD-Combined in autism (80% in our study) largely explains the high prevalence of ODD in autism.” 

Clinical Implications: Why This Study Matters

The researchers point to a straightforward recommendation: clinicians shouldn’t evaluate these conditions in isolation. A child referred for autism concerns might also be struggling with ADHD. A child referred for ADHD might have undiagnosed ODD. And ignoring one disorder can undermine treatment for the others.

Evidence-based interventions (behavioral therapy, parent training, school supports, and/or medication) can reduce symptoms across all three diagnoses while improving long-term outcomes, including overall quality of life.

Mayes SD, Pardej SK, Waschbusch DA. Oppositional Defiant Disorder in Autism and ADHD. J Autism Dev Disord. 2025 Nov;55(11):4092-4105. doi: 10.1007/s10803-024-06437-9. Epub 2024 Jul 27. PMID: 39066970.

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U.S. Nationwide Study Finds Down Syndrome Associated with 70% Greater Odds of ADHD

The Background:

Down syndrome (DS) is a genetic disorder resulting from an extra copy of chromosome 21. It is associated with intellectual disability. 

Three to five thousand children are born with Down syndrome each year. They have higher risks for conditions like hypothyroidism, sleep apnea, epilepsy, sensory issues, infections, and autoimmune diseases. Research on ADHD in patients with Down syndrome has been inconclusive. 

The Study:

The National Health Interview Survey (NHIS) is a household survey conducted by the National Center for Health Statistics at the CDC. 

Due to the low prevalence of Down syndrome, a Chinese research team used NHIS records from 1997 to 2018 to analyze data from 214,300 children aged 3 to 17, to obtain a sufficiently large and nationally representative sample to investigate any potential association with ADHD. 

DS and ADHD were identified by asking, “Has a doctor or health professional ever diagnosed your child with Down syndrome, Attention Deficit Hyperactivity Disorder (ADHD), or Attention Deficit Disorder (ADD)?” 

After adjusting for age, sex, and race/ethnicity, plus family highest education level, family income-to-poverty ratio, and geographic region, children and adolescents with Down syndrome had 70% greater odds of also having ADHD than children and adolescents without Down syndrome. There were no significant differences between males and females. 

The Take-Away:

The team concluded, “in a nationwide population-based study of U.S. children, we found that a Down syndrome diagnosis was associated with a higher prevalence of ASD and ADHD. Our findings highlight the necessity of conducting early and routine screenings for ASD and ADHD in children with Down syndrome within clinical settings to improve the effectiveness of interventions.” 

June 27, 2025

NEW STUDY: The Cumulative Impact of ADHD, ASD, and Intellectual Disabilities

Neurodevelopmental conditions often coexist, creating a complex web of challenges for affected individuals. A recent study by Hollingdale et al. delves into the cumulative effects of attention deficit hyperactivity disorder (ADHD), autism spectrum disorder (ASD), and intellectual disability (ID) on young people’s behavioral and socio-emotional well-being, as well as their overall functioning as rated by clinicians.

The researchers conducted a cross-sectional analysis of 2768 young individuals aged 3-17 years, with a mean age of approximately 11.5 years. Diagnostic information along with caregiver-rated behavioral and socio-emotional data, and clinician-rated functioning scores, were collected from electronic patient records at the point of initial diagnosis.

The study aimed to understand whether the number of neurodevelopmental conditions—ranging from one to three—correlates with more pronounced behavioral and socio-emotional issues, and lower levels of clinician-rated functioning. The behavioral and socio-emotional aspects were assessed using the Strengths and Difficulties Questionnaire, while the Children's Global Assessment Scale was used to evaluate clinician-rated functioning.

The findings revealed that young people with multiple neurodevelopmental conditions tend to exhibit higher levels of inattention and hyperactivity, greater peer-related problems, reduced prosocial behaviors, and poorer overall functioning. Interestingly, this cumulative impact was more evident in males compared to females, with females only showing significant cumulative effects in clinician-rated functioning.

This research underscores the importance of recognizing the compounded difficulties faced by young people with multiple neurodevelopmental conditions. It highlights the need for tailored interventions that address the unique and overlapping challenges presented by ADHD, ASD, and ID. For practitioners, understanding these cumulative effects is crucial for developing effective treatment plans that can better support the holistic development and well-being of these young individuals.

In conclusion, the presence of multiple neurodevelopmental conditions can significantly affect various domains of a young person’s life, with notable differences between males and females. This study provides a critical insight into the intricate nature of these conditions and calls for a more nuanced approach in both research and clinical practice.

June 18, 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

When ADHD and Epilepsy Overlap, Cognitive Impacts Add Up

The Background:

ADHD and epilepsy are the two most common neurological disorders in children and adolescents. Additionally, they appear as co-diagnoses more often than chance would predict. Roughly a quarter of children with epilepsy also have ADHD, and children with ADHD face a 2.5-times greater risk of developing epilepsy than their peers. 

Clinicians have long suspected that carrying both diagnoses compounds cognitive difficulties, but no rigorous quantitative review has mapped out exactly how much, or in what ways. This new meta-analysis now fills that gap. 

The Study:

The team pooled data from peer-reviewed studies that included children and adolescents diagnosed with both conditions alongside at least one comparison group: children with neither condition, children with epilepsy alone, or children with ADHD alone. To capture the breadth of thinking skills, they constructed a general intelligence factor drawing on six cognitive domains: 

  • Crystallized intelligence — accumulated knowledge and its application 
  • Fluid reasoning — tackling novel problems through logical thinking 
  • Working memory — holding and mentally manipulating information in the short term 
  • Processing speed — executing simple or well-practiced mental tasks quickly 
  • Reaction time — responding rapidly to basic stimuli 
  • Long-term memory and fluency — efficiently storing and later retrieving new information 

The Results:

Across eleven studies (995 participants), children and adolescents with both conditions scored moderately lower on general intelligence than those with epilepsy alone. The same pattern held across all six cognitive domains. Seven studies (785 participants) comparing the dual-diagnosis group with those who had ADHD alone found an equally consistent moderate deficit, replicated in every domain. 

The clearest signal emerged when researchers compared children and adolescents carrying both diagnoses to typically-developing peers. Seven studies covering 427 individuals revealed a substantially larger gap in general intelligence, with the effects of the two conditions appearing to be roughly additive, meaning the combined burden was approximately equal to the sum of each condition's individual impact. This pattern held across five of the six domains. 

The Interpretation:

The results come with meaningful caveats. Variability across individual studies was moderate in the first two comparisons and high in the third, reflecting real differences in how studies were designed, which populations they sampled, and how they measured cognition. While there was no sign of publication bias in the first group, it was not assessed in two of the three analyses. 

The authors describe “a widespread profile of cognitive dysfunction” in children and adolescents with both epilepsy and ADHD, while underscoring that the substantial variability between studies warrants caution in drawing overly precise conclusions. The findings nonetheless carry practical weight: children managing both conditions may need more intensive cognitive screening and support than current clinical practice routinely provides. 

June 3, 2026

Exercise May Ease Social Difficulties in Young People with ADHD, New Meta-Analysis Suggests

The focus on children and adolescents with ADHD often revolves around behavioral issues and academic difficulties, but the social struggles are real. Around 60% of youth with ADHD experience meaningful difficulties in social skills, reading social cues, and forming reciprocal relationships with peers. Over time, these struggles can raise the risk of anxiety and depression. 

Medication remains the primary treatment for ADHD, with stimulants like methylphenidate (Ritalin) being the most commonly prescribed. While effective at reducing core symptoms such as inattention and impulsivity, medication has not been shown to improve social behavior or peer relationships.

The Background: 

Exercise has recently emerged as a promising adjunctive therapy. A newly published meta-analysis examined whether structured physical activity can specifically improve social functioning in young people with ADHD. It builds on a previous review from 2015, addressing gaps that earlier work left open: social outcomes were rarely treated as a primary focus, and no prior analysis had systematically compared exercise types or asked how much exercise is actually needed to see benefits. 

The Study: 

The analysis included 13 randomized controlled trials involving 703 participants aged 6 to 18, all clinically diagnosed with ADHD. Only exercise programs lasting at least four weeks were considered. Studies that combined exercise with other therapies, such as psychotherapy, were excluded to isolate exercise's specific effects. 

The researchers used a technique called network meta-analysis, which allows different interventions to be compared against one another even when they haven't been tested head-to-head, alongside dose-response modeling to identify how much exercise produces the greatest benefit. 

  • Closed-skill exercise: takes place in stable, predictable environments where movements can be planned in advance  (such as in gymnastics, track and field, or strength training). 
  • Open-skill exercise: unfolds in dynamic settings that demand constant adaptation  (team sports such as basketball or soccer, and those requiring specific hand-eye coordination such as table tennis). 
  • Multicomponent exercise blends both: a session might begin with a structured, self-directed drill (closed-skill) before transitioning into reactive, opponent-driven play (open-skill). 
  • Mind-body exercise integrates movement, mental focus, and controlled breathing (includes practices like yoga, tai chi, and qigong). 

Results: 

The most striking results came from closed-skill exercise: across four studies involving 92 participants, it was associated with a very large reduction in social dysfunction. Open-skill exercise, by contrast, showed no measurable improvement across four studies with 91 participants. Multicomponent exercise (the group combining elements of both open- and closed-skill) reported large gains in two smaller studies with 33 participants.  

Mind-body exercise showed a moderate benefit across three studies involving 44 participants. 

The dose-response analysis offered a practically useful finding: 30 to 60 minutes of moderate-intensity exercise per day appeared to produce the best outcomes, with a minimum of roughly 15 to 30 minutes daily needed to achieve any meaningful benefit. 

The Take-Away: 

The results are encouraging but should be interpreted carefully. The number of studies in each category was small (two to three studies each), and sample sizes were modest, meaning the findings may not hold up as more evidence accumulates. The absence of publication bias is reassuring, as is the use of rigorous methodology, but this remains an early-stage evidence base. Larger, well-designed trials are needed before firm clinical recommendations can be made. 

For now, the findings position structured physical activity  (particularly closed-skill and multicomponent exercise) as a plausible complement to existing ADHD treatment, specifically targeting the social difficulties that medication tends not to address. The practical dose guidance is a useful starting point: around half an hour of moderate daily exercise as a minimum, with an hour as the apparent sweet spot. As low-risk additions to a treatment plan go, that’s a relatively accessible bar for most families to consider alongside professional guidance. 

May 24, 2026

Exercise as an ADHD Intervention: What Two Recent Meta-Analyses Tell Us

Exercise has attracted growing attention as an intervention for ADHD. As a potential treatment option for ADHD, it is, of course, highly appealing because it can be low- to no-cost, widely accessible, and free of the side effects that can accompany medication. From previous studies, we know that certain types of exercise may be more effective than others, but do we actually know enough for clinicians to prescribe physical activity as a treatment for ADHD? 

The First Study: Effects on Core ADHD Symptoms 

Despite encouraging findings in individual studies, researchers have lacked clear guidance on which types of exercise work best, at what intensity, and for how long. A meta-analysis by Chen et al. set out to address this by pooling data from 20 randomized controlled trials (RCTs) involving 841 children and adolescents aged 4–18, all of which compared exercise interventions against non-exercising control groups. 

The results were cautiously optimistic. Across standardized symptom scales, exercise produced a small improvement in ADHD symptoms overall. Objective cognitive tests showed a moderate improvement. Emotional and behavioral outcomes, however, showed no significant change. 

To understand what was driving differences between studies, the researchers broke results down by exercise type. Therapeutic and alternative exercises (targeted movements and specific techniques such as those prescribed by physical therapists) were associated with moderate symptom improvements. Mind-body practices (such as yoga or tai chi) showed small-to-moderate gains. Conventional aerobic exercise yielded smaller effects, while skill-based competitive sports showed no measurable benefit. Notably, the variability between individual studies remained high throughout, meaning these categories should be interpreted with some caution. 

Results:

The authors recommend that clinicians and parents consider incorporating therapeutic or alternative exercise sessions twice a week, each lasting 60–90 minutes, as a supplemental strategy alongside existing ADHD treatment. They stop short of calling this definitive, noting that future research should clarify how exercise produces its effects and how it might best be combined with medication or behavioral therapy. 

The Second Study: Effects on Inhibitory Control 

A second meta-analysis, by Zhang et al., zoomed in on a specific and particularly relevant cognitive challenge in ADHD: inhibitory control. Inhibitory control refers to the ability to suppress impulsive responses and tune out irrelevant distractions. This capacity underlies much of the restlessness, interrupting, and difficulty staying on task that characterize the condition. 

This analysis drew on 34 studies with over 1,300 participants spanning all age groups, making it broader in scope than the Chen et al. review. Overall, exercise was associated with a moderate improvement in inhibitory control. When the analysis was restricted to RCTs alone, this finding held up. When studies with a high risk of bias were excluded, however, the effect size dropped to small-to-moderate. 

One notable null result: three studies that used EEG to measure brain activity during inhibitory tasks found no significant effects on the neural signatures most closely tied to this process. This suggests exercise may influence behavior without necessarily changing the underlying brain mechanisms researchers expected, or that current methods aren't yet sensitive enough to detect such changes. 

The dosing question produced some of the more practically useful findings. Single exercise sessions yielded only borderline small improvements. Sustained exercise programs, by contrast, showed moderate improvements, and programs with sessions three times per week produced large gains and had the strongest effect between the two meta-analyses. Exercise intensity and total program duration, perhaps interestingly, were not significant factors. 

Results: 

The authors are measured in their conclusions: exercise shows a real but modest benefit for inhibitory control, and frequency appears to matter more than intensity. They caution against overstating the case for exercise as treatment for ADHD overall, as it did not significantly affect hyperactivity or impulsivity as standalone outcomes, and its neural effects remain unclear. 

The Broader Picture

Ultimately, these two meta-analyses support exercise as a meaningful supplemental intervention for ADHD, particularly for attention and cognitive control, while urging realistic expectations. Neither suggests exercise should replace established treatments. Both are limited by high variability across the underlying studies, and both call for better-designed research to sharpen the guidance available to clinicians and families.