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May 16, 2025

Seven New Meta-analyses Suggest Wide Range of Benefits from Exercise for Persons with ADHD

Seven New Meta-analyses Suggest Wide Range of Benefits from Exercise for Persons with ADHD

ADHD is associated with deficits in executive functions. These are mental processes that enable individuals to plan, focus attention, manage tasks, and regulate emotions. These skills encompass working memory, cognitive flexibility, and inhibitory control, which are crucial for goal-directed behavior and decision-making. 

Working memory, which temporarily stores and processes information, contributes to language development by helping individuals make sense of what they read or hear.  

Cognitive flexibility refers to the ability to change perspectives, adapt thinking strategies, adjust to changing needs and priorities, recognize errors, and grasp opportunities.  

Inhibition switching involves intentional control of attention and emotions, suppressing automatic responses when necessary to prevent inappropriate behavior.  

These elements are critical to academic, social, and professional success. 

An international study team (Li et al.) conducted a meta-analysis of randomized controlled trials (RCTs) to explore the efficacy of physical activity for improving executive functions among children with ADHD aged 6 to 12. 

Meta-analysis of eleven RCTs encompassing 388 children reported a medium-to-large effect size improvement in cognitive flexibility. However, it found no benefit from aerobic exercise (such as running, jumping). When limited to the nine studies with 301 children that focused on cognitively engaging exercise (such as soccer and water sports that require constant monitoring of other players and strategizing), it found a large effect size improvement. Correcting for possible publication bias had no effect on the outcome. 

Meta-analysis of nine RCTs totaling 398 children reported a large effect size improvement in working memory. Once again, it found no benefit from aerobic exercise. Focusing on the seven RCTs with 288 children that used cognitively engaging exercise, it found a very large effect size improvement. There was no sign of publication bias. 

Meta-analysis of fourteen RCTs combining 579 children reported a small-to-medium effect size improvement in inhibition switching. But whereas it found a medium effect size improvement for shorter interventions of less than an hour (eight RCTs, 334 children), it found no benefit from interventions lasting an hour or more (six RCTs, 245 children. Again, there was no sign of publication bias. 

The team concluded, “Our study shows that physical activity interventions have a positive effect on improving executive function in school-age children with ADHD, with cognitive-engaging exercises showing greater benefits across three executive function measures.” 

A Chinese study team (Yang et al.) performed a related meta-analysis on the effect of exercise on inhibitory control in adults. Combining eight RCTs with a total of 372 participants, it reported a very large effect size improvement in inhibitory control, primarily from regular exercise. However, the effects were heavily influenced by a couple of outliers. The team claimed to have performed a sensitivity analysis but offered no evidence. Likewise, they noted signs of publication bias but did not use the standard trim-and-fill analysis to correct for it. 

Another Chinese study team (Xiangqin Song et al.) examined the effect of exercise on working memory in children and adolescents.  

Meta-analysis of 17 RCTs encompassing 419 participants found a medium effect size improvement in working memory. The large effect size improvement for cognitive aerobic exercise (4 RCTs, 233 participants) was twice the effect size for simple aerobic exercise (8 RCTs, 397 participants), though this meta-analysis still found a small-to-medium effect size gain from the latter. There was no sign of publication bias.  

The team concluded, “The results indicate that cognitive-aerobic exercise and ball sports are significantly more effective than other types of exercise interventions in improving working memory. This difference may be attributed to the varying cognitive load, task complexity, and the degree of activation of executive functions across different exercise types. The findings suggest that when designing exercise interventions for children with ADHD, priority should be given to exercise types with higher cognitive load in order to more effectively enhance working memory.” 

A joint Australian-U.S. team (Singh et al.) conducted a meta-meta-analysis on the effect of exercise on executive functions, that is, a meta-analysis of previous meta-analyses of RCTs.  

Combining ten separate meta-analyses with well over 2,800 children and adolescents with ADHD, it reported large effect size improvements in executive functions overall. There was no further breakdown by type of executive function and type of physical activity.  

The team concluded, “While exercise was seen to have a moderate and similar positive impact across all populations with respect to general cognition and memory, benefits for executive function were particularly marked in individuals with ADHD. This subgroup was unique in demonstrating a large effect size. This could be attributed to the task selection and the fact that many ADHD studies involved children. While the exact reason for this finding is unclear, there is evidence to suggest that impairments in executive function are common among individuals with ADHD. As such, it is plausible that this population may have a greater capacity for improvement due to starting from a lower baseline, compared with those with ‘normal’ executive function.” 

Another Chinese study team (Yagang Song et al.) performed a meta-analysis of RCTs examining the effects of physical exercise on anxiety, depression, and emotion regulation among children and adolescents with ADHD.  

Meta-analysis of eleven studies with a combined total of 384 participants reported a medium effect size reduction in symptoms of anxiety, with a dose-effect response. Physical exercise once a week had no significant effect, while twice a week was associated with a medium effect size reduction, and three or more times a week with a very large effect size improvement. Moderate intensity exercise was three times more effective than low intensity exercise.  

Meta-analysis of seven studies encompassing 187 individuals similarly reported a medium effect size reduction in symptoms of depression. Once again, moderate intensity was far more effective than low intensity exercise. 

Meta-analysis of seven studies totaling 429 children and adolescents reported a very large effect size improvement in emotion regulation, especially for physical exercise conducted at least twice a week

There was no sign of publication bias in the anxiety, depression, or emotion regulation findings. 

The team concluded, “Physical exercise demonstrated a substantial overall impact on enhancing anxiety, depression, and emotional regulation in children with ADHD, exhibiting a dose-response effect correlated with the period, frequency, duration, and intensity of the exercise. This investigation ... presents an additional evidence-based therapeutic approach for the considerable number of children with ADHD who are not appropriate candidates for pharmacological intervention.” 

A joint U.S.-Hong Kong study team (Liu et al.) performed a meta-analysis exploring the effect of physical exercise on motor proficiency. Motor proficiency includes both gross motor skills (like walking and running) and fine motor skills (like writing and buttoning).  

Meta-analysis of ten studies encompassing 413 children and adolescents with ADHD reported a very large effect size improvement in motor proficiency from physical exercise. The gains for object control, fine manual control, and manual coordination were roughly twice the gains for body coordination. There was no sign of publication bias. 

Finally, a Spanish research team (González-Devesa et al.) conducted a meta-analysis examining the effect of exercise on objectively measured sleep status among persons with ADHD. 

Meta-analysis of three RCTs with a combined total of 131 individuals that used accelerometers to measure sleep duration reported no significant effect one way or the other from exercise

The team concluded, “The existing evidence regarding the use of exercise to manage sleep problems in individuals with ADHD remains inconclusive. Preliminary findings from this review suggest a potential positive effect of exercise on self-reported sleep quality; however, its efficacy in improving sleep duration could not be confirmed.” 

The Take-Away:

An ideal exercise regimen for children with ADHD should focus on cognitively engaging physical activities rather than simple aerobic exercise. Sports and activities that require strategic thinking, attention to others’ actions, and rapid decision-making—such as soccer, martial arts, or water-based team sports—gave the best results, especially for working memory and cognitive flexibility. These types of exercise also show strong benefits for emotional regulation, reducing anxiety and depression, and enhancing motor proficiency.

To maximize benefits, the regimen should include moderate-intensity sessions at least two to three times per week, each lasting less than an hour, as longer durations appear less effective for improving inhibitory control. This structured, cognitively demanding approach offers an evidence-based, non-pharmacologic treatment option for children with ADHD, particularly for those who cannot or prefer not to use medication.  We need, however, more work to determine if exercise will provide the same symptom reduction and protection from adverse outcomes as has been shown for medications.

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Love, Sex and ADHD

Love, Sex and ADHD

Research on ADHD has extensively explored various aspects of the condition, yet surprisingly little attention has been devoted to its impact on romantic relationships. Despite over 25,000 articles on ADHD listed in PubMed, only a small number examine topics such as love, sex, and relationship dynamics.

One study by Brunner and colleagues analyzed ADHD symptoms and romantic relationship quality in 189 college students. The findings indicated that students with high levels of hyperactivity-impulsivity and inattentiveness reported lower relationship quality compared to peers with fewer ADHD symptoms. Similarly, a study of 497 college students revealed that ADHD symptoms were linked to the use of maladaptive coping strategies in relationships, resulting in reduced romantic satisfaction.

In research involving young adults, ADHD symptoms were associated with greater negativity and reduced positivity during conflict resolution tasks within romantic partnerships. Higher levels of ADHD symptoms were predictive of lower relationship satisfaction. However, couples where the ADHD partner displayed only inattentive symptoms experienced fewer relational challenges, suggesting that the severity and type of symptoms significantly influence outcomes.

Regarding sexual behavior, studies highlight distinct patterns among individuals with ADHD. Adolescents with ADHD, regardless of gender, report nearly double the number of lifetime sexual partners compared to their non-ADHD peers. These findings align with research by Barkley and colleagues, who observed that ADHD predicted earlier sexual activity and parenthood. Similarly, Flory and colleagues, in a retrospective study, found that childhood ADHD was associated with earlier sexual initiation, more sexual partners, casual relationships, and unintended pregnancies.

A broader study of over 1,000 adults found that ADHD was associated with less stability in romantic relationships, difficulty providing emotional support, higher rates of sexual dysfunction, and increased divorce rates.

Although the body of research on ADHD and romantic relationships is relatively small, it consistently highlights the significant impact of ADHD on love, sex, and relational dynamics, often presenting unique challenges for those affected.

May 5, 2021
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Is ADHD a Serious Condition?

Is ADHD a Serious Condition?

In the popular media, ADHD has sometimes been portrayed as a minor condition or not a disorder at all. It is easy to find websites claiming that ADHD is an invention of the medical profession and that the symptoms used to diagnose the disorder are simply normal behaviors that have been "medicalized". These claims are wrong. They miss the main point of any psychiatric diagnostic process, which is to identify people who experience distress or disability due to a set of well-defined symptoms. So, does ADHD cause serious distress and disability? It is a serious psychiatric condition? To illustrate the strong evidence base for the "Yes" answer to that question, my colleagues and I constructed this infographic for our "Primer" about ADHD,http://rdcu.be/gYyV.It describes the many ways in which the symptoms of ADHD impact and impair the lives of children, adolescents, and adults with the disorder. We divided these 'impacts' into four categories: other disorders (both psychiatric and medical), psychological dysfunction, academic and occupational failure, social disability, and risky behaviors. Let's start with other health problems. We know from many studies that have followed ADHD children into adolescence and adulthood that having the disorder puts patients at risk for several psychiatric disorders, addictions, criminality, learning disabilities, and speech/language disorders. ADHD even increases the risk for-psychiatric diseases such as obesity, hypertension, and diabetes. Perhaps most worrisome is that people with ADHD have a small increased risk for premature death. This increased risk is due in part to their having other psychiatric and medical conditions and also to their risky behaviors which, as research documents, lead to accidents and traumatic brain injuries. In the category of psychological dysfunction,' we highlighted emotional dysregulation, which makes ADHD people quick to anger or fail to tame extreme emotions. Other serious psychological issues are low self-esteem and increased thoughts of suicide, which lead to more suicide attempts than for people without ADHD. This increased risk for suicide is small, but it is real. A more prevalent impact of ADHD is the broad category of social disability, which includes marital discord, poor parenting, legal problems, arrests, and incarceration. This typically starts in youth with poor social adjustment and conflict with parents, siblings, and friends. Another common impact of ADHD is on academic and vocational pursuits. ADHD youth are at risk for underachievement in school, repeating grades, and dropping out. As adults, they are more likely to be unemployed or underemployed, which leads to them having lower incomes than expected for their level of school achievement. So, don't believe anyone who claims that ADHD is not a disorder or is only a mild one. To be sure, there is a wide range of impairments among people with ADHD but, in the absence of treatment, they are at risk for adverse outcomes. Fortunately, the medications that treat ADHD have been documented to reduce this risk, which is why they are typically the first-line treatment for most people with ADHD.

May 3, 2021
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Is ADHD A Serious Conidtion?

How Serious is ADHD?

The US Center for Disease Control's (CDC)review of ADHD starts with the statement: "Attention-deficit/hyperactivity disorder (ADHD) is a serious public health problem affecting many children and adults" (http://www.cdc.gov/ncbddd/adhd/research.html). My colleagues and I recently reviewed the ADHD literature. That let us describe ADHD as "... a seriously impairing, often persistent neurobiological disorder of high prevalence..." (Faraone et al., 2015). The figure 1, which comes from that paper, provides an overview of the lifetime trajectory of ADHD-associated morbidity.

Especially compelling data about ADHD and injuries comes from a recent paper, in Lancet Psychiatry, which used the Danish national registers to follow a cohort of 710,120 children (Dalsgaard et al., 2015a).   Compared with children not having ADHD, those with ADHD were 30% more likely to sustain injuries than other children.  Pharmacotherapy for ADHD reduced the risk for injuries by 32% from 5 to 10 years of age. Pharmacotherapy for ADHD reduced emergency room visits by 28.2% at age 10and 45.7% at age 12.    

These results are shown in Figure 2, taken from the publication.

Especially compelling data about ADHD and injuries comes from a recent paper, in Lancet Psychiatry, which used the Danish national registers to follow a cohort of 710,120 children (Dalsgaard et al., 2015a).   Compared with children not having ADHD, those with ADHD were 30% more likely to sustain injuries than other children.  Pharmacotherapy for ADHD reduced the risk for injuries by 32% from 5 to 10 years of age. Pharmacotherapy for ADHD reduced emergency room visits by 28.2%at age 10and 45.7% at age 12.    

These results are shown in Figure2, taken from the publication.  The Figure compares the prevalence of injuries among three groups.  ADHD children treated with medication, ADHD children not treated with medication, and children without ADHD.  The Figure shows how ADHD risk for injuries occurs for all age groups. It also shows how the risk for injuries drops with treatment so that by age 12, the prevalence of injuries among treated ADHD children is the same as the prevalence of injuries for children without ADHD.

Documented examples of ADHD-associated injuries which impact day-to-day functioning include severe burns (Fritz and Butz, 2007), dental injuries (Sabuncuoglu, 2007), penetrating eye injuries (Bayar et al., 2015), the hospital treated injuries (Hurtig et al., 2013), and head injuries (DiScala et al., 1998).  In one study (DiScala et al., 1998), when compared to other children admitted to the hospital for injuries, ADHD children were more likely to sustain injuries in multiple body regions (57.1% vs 43%), sustain head injuries (53% vs 41%), and to be severely injured as measured by the Injury Severity Score (12.5% vs5.4%) and the Glasgow Coma Scale (7.5% vs 3.4%).

Injuries are a substantial cause of ADHD-associated premature death.  This assertion comes from the work of Dalsgaard et al. (2015b)based on the same Danish registry discussed above.   In this second study, ADHD was associated with an increased risk for premature death and 53% of those deaths were due to injuries.  They reported the risk for premature death in three age groups: 1-5, 6-17, and >17.  For all three age groups, they found a greater risk for death in the ADHD group. For ages 6 to 17 and greater than 17. The ADHD-associated risk for mortality remained significant after excluding individuals with antisocial or substance use disorders.

There are currently no data about the effect of ADHD treatment on ADHD-associated premature death.  We do, however, know from the data reviewed above that ADHD treatment reduces injuries and that half the deaths in the ADHD group were due to injuries.  From this, we infer that ADHD treatments could reduce the risk of ADHD-associated premature death.

Two other ADHD-associated mobilities, obesity and cigarette smoking, have clear medical consequences.  In a meta-analysis of 42 cross-sectional studies comprising 48,161 people with ADHD and 679,975 controls, my colleagues and I reported that the pooled prevalence of obesity was increased by about 40% in ADHD children compared with non-ADHD children and by about 70% in ADHD adults compared with non-ADHD adults(Cortese et al.,2015). The association between ADHD and obesity was significant for ADHD medication-naïve subjects but not for those medicated for ADHD, which suggests that medication reduces the risk for obesity.  

Likewise, a meta-analysis of 27 longitudinal studies assessed the risk for several addictive disorders with sample sizes ranging from 4142 to 4175 for ADHD and 6835 to 6880 for non-ADHD controls (Lee et al., 2011).  Children with ADHD were at higher risk for disorders of abuse or dependence on nicotine, alcohol, marijuana, cocaine, and other unspecified substances.  Another meta-analysis (42 studies totaling, 2360 participants) showed that medications for ADHD reduced the ADHD-associated risk for smoking (Schoenfelder et al., 2014).   The authors concluded that, for ADHD patients, "Consistent stimulant treatment for ADHD may reduce the risk of smoking". This finding is especially notable given that, for ADHD youth, cigarette smoking is a gateway drug to more serious addictions (Biederman et al., 2006).

 Yes, ADHD is a serious disorder.  Although most ADHD people will be spared the worst of these outcomes, they must be considered by parents and patients when weighing the pros and cons of treatment options.

November 16, 2023
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How to Avoid False Positives and False Negatives when Diagnosing Adult ADHD

How to Avoid False Positives and False Negatives when Diagnosing Adult ADHD?

A recent paper by Margaret Sibley and colleagues addresses a key issue in the diagnosis of adult ADHD. Is it sufficient to only collect data from the patient being diagnosed or are informants useful or, perhaps, essential, for diagnosing ADHD in adults? Dr. Sibley presented a systematic review of twelve studies that prospectively followed ADHD children into adulthood. Each of these studies asked a simple question: What fraction of ADHD youth continued to have ADHD in adulthood. Surprisingly, the estimates of ADHD's persistence ranged from a low of4% to a high of 77%. They found two study features that accounted for much of this wide range. The first was the nature of the informant; did the study rely only on the patient's report, or were other informants consulted. The second was the use of a strict diagnostic threshold of six symptoms. When they limited the analysis to studies that used informants and eliminated the six symptom threshold, the range of estimates was much narrower, 40% to 77%. From studies that computed multiple measures of persistence using different criteria, the authors concluded: "(1) requiring impairment to be present for diagnosis reduced persistence rates; (2) a norm-based symptom threshold led to higher persistence than a strict six-symptom DSM-based symptom count criterion; and (3) informant reports tended to show a higher number of symptoms than self-reports." These data have clear implications for what clinicians can do to avoid false positive and false negative diagnoses when diagnosing adult ADHD. It is reassuring that the self-reports of ADHD patients tend to underestimate the number and severity of ADHD symptoms. This means that your patients are not typically exaggerating their symptoms. Put differently, self-reports will not lead you to over-diagnose adult ADHD. Instead, reliance on self-reports can lead to false-negative diagnoses, i.e., concluding that someone does not have ADHD when, in fact, they do. You can avoid false negatives by doing a thorough assessment, which is facilitated by some tools available at www. ADHD in adults. Command described in CME videos there. If you think a patient might have ADHD but are not certain, it would be helpful to collect data from an informant, i.e., someone who knows the patient well such as a spouse, partner, roommate, or parent. You can collect such data by sending home a rating scale or by having the patient bring an informant to a subsequent visit. Dr. Sibley's paper also shows that you can avoid false-negative diagnoses by using a lower symptom threshold than what is required in the diagnostic manual. The new DSM 5 lowered the symptom threshold for adults from six to five. Can you go lower? Yes, but it is essential to show that these symptoms lead to clear impairments in living. Importantly, this symptom threshold refers to the number of symptoms documented in adulthood, not to the number of symptoms retrospectively reported in childhood. To be diagnosed with ADHD in adulthood, one must document that the patient had at least six impairing symptoms of ADHD before the age of 12.

April 29, 2021
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What Can Doctors Do About Those Faking ADHD?

What can Doctors do about Fake ADHD?

ADHD is a serious disorder that requires treatment to prevent many adverse outcomes. But, because the diagnosis of ADHD is based on how the patient responds to questions, people can pretend that they have ADHD when they do not. If you Google "fake ADHD" you'll get many pages of links, including a Psychology Today article on the topic and bloggers describing how they were able to fool doctors into giving them ADHD medications. Is fake ADHD a serious problem? Not really. The Internetseems to be faking an epidemic of fake ADHD.I say that because we have decades of research that show many objective measures of abnormality and impairment in people who say they have ADHD. These include traffic accidents, abnormalities in brain imaging, and molecular genetic differences. Some studies even suggest that ADHD adults downplay their ADHD symptoms. For example, one study diagnosed ADHD in children and then contacted them many years later when they were young adults.When they were interviewed as young adults, their responses to questions about ADHD suggested that they did not have the disorder. But when the same questions about the patient were asked to someone who lived with the patient as a young adult, it was clear that they still had ADHD. So rather than faking ADHD, many ADHD adults do not recognize that they have symptoms of the disorder. That said, we also know from research studies that, when asked to pretend that they have ADHD, adults can fake the disorder. That means that they can learn about the symptoms of the disorder and makeup examples of how they have had them when they have not. The research discussed above suggests that this is not common, but we do know that some people have motives for faking ADHD.For example, some college students seek special accommodations for taking tests; others may want stimulants for abuse, misuse, or diversion. Fortunately, doctors can detect fake ADHD in several ways. If an adult itself-referred for ADHD and asks specifically for stimulant medication, that raises the possibility of fake ADHD and drug-seeking. Because the issue of stimulant misuse has been mostly a concern on college campuses, many doctors treating college students will require independent verification of the patient's ADHD symptoms by speaking with a parent, even over the phone if an in-person visit is not possible. Using ADHD rating scales will not detect fake ADHD, and it is easy to fake poor performance on tests of reading or math ability. Neuropsychological tests can sometimes be used to detect malingering, but require referral to a specialist. Researchers are developing methods to detect faking ADHD symptoms. These have shown some utility in studies of young adults, but are not ready for clinical practice. So, currently, doctors concerned about fake ADHD should look for objective indicators of impairment (e.g., documented traffic accidents; academic performance below expectation) and speak to a parent of the patient to document that impairing symptoms of the disorder were present before the age of twelve. Because the issue of fake ADHD is of most concern on college campuses, it can also be helpful to speak with a teacher who has had frequent contact with the patient. In an era of large lecture halls and broadcast lectures, that may be difficult. And don't be fooled by the Internet. We don't want to deny treatment to ADHD patients out of undocumented reports of an epidemic of fake ADHD.

April 27, 2021
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Attention Deficit Hyperactivity Disorder: Fact vs. Fiction

Attention Deficit Hyperactivity Disorder: Fact vs. Fiction

Many myths have been manufactured about attention deficit hyperactivity disorder (ADHD).  Facts that are clear and compelling to most scientists and doctors have been distorted or discarded from popular media discussions of the disorder.   Sometimes, the popular media seems motivated by the maxim "Never let the facts get in the way of a good story."  That's fine for storytellers, but it is not acceptable for serious and useful discussions about ADHD.

Myths about ADHD are easy to find.  These myths have confused patients and parents and undermined the ability of professionals to appropriately treat the disorder.   When patients or parents get the idea that the diagnosis of ADHD is a subjective invention of doctors, or that ADHD medications cause drug abuse, that makes it less likely they will seek treatment and will increase their chances of having adverse outcomes. 

Fortunately, as John Adams famously said of the Boston Massacre, "Facts are stubborn things."  And science is a stubborn enterprise; it does not tolerate shoddy research or opinions not supported by fact.   ADHD scientists have addressed many of the myths about the disorder in the International Consensus Statement on ADHD, a published summary of scientific facts about ADHD endorsed by 75 international ADHD scientists in2002.  The statement describes evidence for the validity of ADHD, the existence of genetic and neurobiological causes for the disorder, and the range and severity of impairments caused by the disorder.   

The Statement makes several key points:

  • The     U.S. Surgeon General, the American Medical Association, the American     Psychiatric Association, the American Academy of Child and Adolescent Psychiatry, the     American Psychological Association, and the American Academy of Pediatrics recognize ADHD as a valid disorder.
  • ADHD     involves a serious deficiency in a set of psychological abilities, and these deficiencies pose serious harm to most individuals possessing the disorder.
  • Many studies show that the psychological deficits in people with ADHD are associated with abnormalities in several specific brain regions.
  • The genetic contribution to ADHD is routinely found to be among the highest for any psychiatric disorder.
  • ADHD     is not a benign disorder. For those it afflicts, it can cause devastating problems.

The facts about ADHD will prevail if you take the time to learn about them. This can be difficult when faced with a media blitz of information and misinformation about the disorder. In future blogs, I'll separate the fact from the fiction by addressing several popular myths about ADHD.

April 25, 2021
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What is Evidenced-Based Medicine?

What is Evidenced-Based Medicine?

With the growth of the Internet, we are flooded with information about attention deficit hyperactivity disorder from many sources, most of which aim to provide useful and compelling "facts" about the disorder.  But, for the cautious reader, separating fact from opinion can be difficult when writers have not spelled out how they have come to decide that the information they present is factual. 

My blog has several guidelines to reassure readers that the information they read about ADHD is up-to-date and dependable. They are as follows:

Nearly all the information presented is based on peer-reviewed publications in the scientific literature about ADHD. "Peer-reviewed" means that other scientists read the article and made suggestions for changes and approved that it was of sufficient quality for publication. I say "nearly all" because in some cases I've used books or other information published by colleagues who have a reputation for high-quality science.

When expressing certainty about putative facts, I am guided by the principles of evidence-based medicine, which recognizes that the degree to which we can be certain about the truth of scientific statements depends on several features of the scientific papers used to justify the statements, such as the number of studies available and the quality of the individual studies. For example, compare these two types of studies.  One study gives drug X to 10 ADHD patients and reported that 7 improved.  Another gave drug Y to 100 patients and a placebo to 100 other patients and used statistics to show that the rate of improvement was significantly greater in the drug-treated group. The second study is much better and much larger, so we should be more confident in its conclusions. The rules of evidence are fairly complex and can be viewed at the Oxford Center for Evidenced Based Medicine (OCEBM;http://www.cebm.net/).


The evidenced-based approach incorporates two types of information: a) the quality of the evidence and b) the magnitude of the treatment effect. The OCEBM levels of evidence quality are defined as follows (higher numbers are better:

  1. Mechanism-based reasoning.  For example, some data suggest that oxidative stress leads to ADHD, and we know that omega-3 fatty acids reduce oxidative stress. So there is a reasonable mechanism whereby omega-3 therapy might help ADHD people.
  2. Studies of one or a few people without a control group, or studies that compare treated patients to those that were not treated in the past.

Non-randomized, controlled studies.    In these studies, the treatment group is compared to a group that receives a placebo treatment, which is a fake treatment not expected to work.  

  1. Non-randomized means that the comparison might be confounded by having placed different types of patients in the treatment and control groups.
  2. A single randomized trial.  This type of study is not confounded.
  3. Systematic review and meta-analysis of randomized trials. This means that many randomized trials have been completed and someone has combined them to reach a more accurate conclusion.

It is possible to have high-quality evidence proving that a treatment works but the treatment might not work very well. So it is important to consider the magnitude of the treatment effect, also called the "effect size" by statisticians. For ADHD, it is easiest to think about ranking treatments on a ten-point scale. The stimulant medications have a quality rating of 5 and also have the strongest magnitude of effect, about 9 or 10.Omega-3 fatty acid supplementation 'works' with a quality rating of 5, but the score for the magnitude of the effect is only 2, so it doesn't work very well. We have to take into account patient or parent preferences, comorbid conditions, prior response to treatment, and other issues when choosing a treatment for a specific patient, but we can only use an evidence-based approach when deciding which treatments are well-supported as helpful for a disorder.

April 23, 2021
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How do Stimulants Modulate the Brain to Improve ADHD Symptoms?

How do Stimulants Modulate the Brain to Improve ADHD Symptoms?

The stimulants methylphenidate and amphetamine are well known for their efficacy in treating symptoms of ADHD in both youth and adults.   Although these medications have been used for several decades, relatively little is known about the mechanisms of action that lead to their therapeutic effect.    

New data about the mechanism comes from a meta-analysis by Katya Rubia and colleagues. They analyzed 14 functional magnetic resonance imaging (fMRI) data sets comprising 212 youth with ADHD.  Each of these data sets assessed the short-term effects of stimulants on fMRI-assessed brain activations. In the fMRI paradigm, ADHD and control participants are asked to do a neurocognitive task while the activity of their brains is being measured. Dr. Rubia and colleagues analyzed data from fMRI assessments of time discrimination, inhibition, and working memory, each of which is known to be deficient in ADHD patients.    

The meta-analysis found that the most consistent brain activations were seen in a region comprising the right inferior frontal cortex(IFC) and insula, even when the analysis was limited to previously medication-naïve patients. The implicated region of the brain is known to mediate cognitive control, time estimation, and attention.  Dr.Rubia also notes that other studies show that the IFC/Insula is needed for updating information and allocating attention to relevant stimuli.  

Another region implicate by the meta-analysis was the right putamen, a region that is rich in dopamine transporters. This finding is consistent with the fact that the dopamine transporter is the main target of stimulant medications.    

What is the potential clinical implication of these findings?  As Dr. Rubia and colleagues note, it is possible that the fMRI anomalies they identified could be used as a biomarker for ADHD or a biomarker to select patients who should respond optimally to stimulant medication. Although fMRI cannot be used as a clinical tool at this time, research of this sort is opening up new horizons for how we understand the etiology of ADHD and the mechanisms whereby medications exert their effects.

April 21, 2021
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Cognitive Behavioral Therapy for ADHD: What is it? Does it work?

Cognitive Behavioral Therapy for ADHD: What is it? Does it work?

Cognitive Behavioral Therapy (CBT) is a one-to-one therapy, for adolescents or adults, where a therapist teaches an ADHD patient how thoughts, feelings, and behaviors are all interrelated and how each of these elements affects the others.  CBT emphasizes cognition or thinking because a major goal of this therapy is to help patients identify thinking patterns that lead to problem behaviors.  For example, the therapist might discover that the patient frequently has negative automatic thoughts such as "I'm stupid" in challenging situations. We call the thought 'automatic' because it invades the patient's consciousness without any effort. Thinking "I'm stupid" can cause anxiety and depression, which leads to failure. Thus, stopping the automatic thought will modify this chain of events and, hopefully, improve the outcome from failure to success.

CBT also educates patients about their ADHD and how it affects them in important daily activities.


For example, most ADHD patients need help with activity schedules, socializing, organizing their workspace, and controlling their distractibility. By teaching specific cognitive and behavioral skills, the therapist helps the patient deal with their ADHD symptoms productively. For example, some ADHD patients are very impulsive when conversing with others. They don't wait their turn during conversations and may blurt out irrelevant ideas. This can be annoying to others, especially in the context of school or business relationships. The CBT therapist helps the patient identify these behaviors and creates strategies for avoiding them.

So, does CBT work for ADHD? The evidence base is small, but when CBT has been used for adult ADHD, it has produced positive results in well-designed studies.   These studies typically compare patients taking ADHD medications with those taking ADHD medications and receiving CBT.  

So for now, it is best to consider CBT as an adjunct rather than a replacement for medication. There are even fewer studies of CBT for adolescents with ADHD.  These initial studies also suggest that CBT will be useful for adolescents with ADHD who are also taking ADHD medications.  Some data suggest that CBT can be successfully applied in the classroom, but the evidence base is very small.

How can this information be used by doctors and patients for treatment planning?  Current treatment guidelines suggest starting with an ADHD medication.  After a suitable medication and dose are found, the patient and doctor should determine if any problems remain.  If so, CBT should be considered an adjunct to ADHD medications.

April 19, 2021
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Is Cognitive Behavior Therapy Effective for Treating Adult ADHD?

Is Cognitive Behavior Therapy Effective for Treating Adult ADHD?

The term "cognitive behavior therapy (CBT)" refers to a type of talk therapy that seeks to change the way patients think about themselves, their disorder, and the world around them in a manner that will help them overcome symptoms and achieve life goals.

Because CBT is typically administered by a psychologist or other mental health professionals, CBT services are not available in primary care. Nonetheless, it is useful for primary care practitioners to know about CBT so that they can refer appropriately as needed. So, what can we say about the efficacy of CBT for treating adults with ADHD?

Based on a meta-analysis by Young and colleagues, we know for certain that the number of published trials of CBT for adult ADHD is small; only nine trials are available. Five of these compared CBT with waiting list controls; three compared CBT with appropriate placebo control groups. In all of these studies, patients in the CBT and control groups were also being treated with ADHD medications.

Thus, they speak to the efficacy of CBT when given as an adjunctive treatment. The meta-analysis examined the waiting list controlled studies and the placebo-controlled studies separately. For both types of study, the effect of CBT in reducing ADHD symptoms was statistically significant, with a standardized mean effect size of 0.4.

This effect size, albeit modest, is large enough to conclude that CBT will be useful for some patients being treated with ADHD medications. Given these results, a reasonable guideline would be to refer adults with ADHD to a CBT therapist if they are being maintained on an ADHD medication, but that medication is not leading to a complete remission of their symptoms and impairments. So listen to your patients. If, while on an appropriately titrated medication regime, they still complain about unresolved symptoms or impairments, you need to take action.  In some cases, changing their dose or shifting to another medication will be useful. If such approaches fail or are not feasible, you should consider referral to a CBT therapist.

April 17, 2021
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