July 18, 2021

Immediate and longer-term effects of exerciseon ADHD symptoms and cognition

A team of Spanish researchers has published a systematic review of 16 studies with a total of 728 participants exploring the effects of physical exercise on children and adolescents with ADHD. Fourteen studies were judged to be of high quality, and two of medium quality.

Seven studies looked at the acute effects of exercise on eight to twelve-year-old youths with ADHD. Acute means that the effects were measured immediately after periods of exercise lasting up to 30 minutes. Five studies used treadmills and two used stationary bicycles, for periods of five to 30 minutes. Three studies "showed a significant increase in the speed of reaction and precision of response after an intervention of 20-30 min, but at moderate intensity (50-75%)." Another study, however, found no improvement in mathematical problem-solving after 25 minutes using a stationary bicycle at low (40-50%) or moderate intensity (65-75%). The three others found improvements in executive functioning, planning, and organization in children after 20- to 30-minute exercise sessions.

Nine studies examined longer-term effects, following regular exercise over many weeks. One reported that twenty consecutive weekly yoga sessions improved attention. Another found that moderate to vigorous physical activity (MVPA) led to improved behavior beginning in the third week, and improved motor, emotional and attentional control, by the end of five weeks. A third study reported that eight weeks of starting the school day with 30 minutes of physical activity led to improvement in Connor's ADHD scores, oppositional scores, and response inhibition. Another study found that twelve weeks of aerobic activity led to declines in bad mood and inattention. Yet another reported that thrice-weekly 45-minute sessions of MVPA over ten weeks improved not only muscle strength and motor skills, but also attention, response inhibition, and information processing.

Two seventy-minute table tennis per week over twelve weeks improved executive functioning and planning, in addition to locomotor and object control skills.

Two studies found a significant increase in brain activity. One involved two hour-long sessions of rowing per week for eight weeks, the other three 90-minute land-based sessions per week for six weeks. Both studies measured higher activation of the right frontal and right temporal lobes in children, and lower theta/alpha ratios in male adolescents.

All 16 studies found positive effects on cognition. Five of the nine longer-term studies found positive effects on behavior. No study found any negative effects. The authors of the review concluded that physical activity "improves executive functions, increases attention, contributes to greater planning capacity and processing speed and working memory, improves the behavior of students with ADHD in the learning context, and consequently improves academic performance." Although the data are limited by a lack of appropriate controls, they suggest that, in addition to the well-known positive effects of physical activity, one may expect to see improvements in ADHD symptoms and associated features, especially for periods of sustained exercise.

Sara Suarez-Manzano, Alberto Ruiz-Ariza, Manuel La Torre-Cruz, Emilio J. MartiÌnez-LoÌpez, "Acute and chronic effect of physical activity on cognition and behavior in young people with ADHD: A systematic review of intervention studies," Research in Developmental Disabilities, vol. 77, 12-23(2018).

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Swedish Population Study Confirms Association Between ADHD and Height

Nationwide population study in Sweden confirms association between ADHD and shorter height in children and adolescents, suggests stimulant medications are not a factor

A commonly reported risk associated with ADHD medication is reduced growth in height. But studies to date have generally not adequately described or measured possible confounders, such as genetic factors, prenatal factors, or socioeconomic factors. What if ADHD were associated with reduced height even in the absence of medications? 

An international study team explored this question by performing a nationwide population study comparing data from before (1968-1991) and after (1992-2020) the adoption of stimulant therapy for ADHD in Sweden. 

The country’s single-payer health insurance system that connects patient records with all other national registers through unique personal identification numbers makes such analysis possible. Sweden also has military service conscription, which records the heights of 18-year-old males.

The participants were all 14,268 Swedish males with a diagnosis of ADHD who were drafted into military service at any time from 1968 through 2020. 

Up to five non-ADHD controls were identified for each ADHD case, matched by sex (they had to be male), birth year, and county. The total number of controls was 71,339.

Among 34,586 participants in the period before adoption of stimulant medications (1968-1991), those diagnosed with ADHD had roughly 30% greater odds of being shorter than normal (166-172 vs. 173-185 cm) than typically developing controls. That dropped to 20% greater odds among the 34,714 participants in the cohort following adoption of stimulant medications.

The odds of those diagnosed with ADHD being much shorter than normal (150-165 vs. 173-185 cm) remained identical (about 55% greater) among the almost 30,000 participants in both cohorts.

In other words, there was no increase in the odds of ADHD individuals being shorter than normal after adoption of stimulant therapy in Sweden compared with before such adoption.

Furthermore, after adjusting for known confounders, including birth weight, inflammatory bowel disease, celiac disease, hypothyroidism, anxiety disorders, depression, substance use disorder, and highest parental education, the odds of those diagnosed with ADHD being shorter than normal or much shorter than normal in the 1992-2020 cohort dropped to roughly 10% and 30% greater, respectively.

Could it be the disorder itself rather than stimulant treatment that is associated with reduced height in individuals diagnosed with ADHD?

To address effects of environmental and familial/genetic confounding, the team then compared the entire cohort of males diagnosed with ADHD from 1968 through 2020 with typically developing male relatives, ranging from first cousins to full siblings.

Among full siblings, the odds of those with ADHD diagnoses being shorter (over 90,000 participants) or much shorter (over 77,000 participants) were a statistically significant 14% and 18%, respectively.

The authors concluded, “Our findings suggest that ADHD is associated with shorter height. On a population level, this association was present both before and after ADHD-medications were available in Sweden. The association between ADHD and height was partly explained by prenatal factors, psychiatric comorbidity, low SES [socioeconomic status] and a shared familial liability for ADHD.”

January 9, 2024

Swedish nationwide population study finds mothers with ADHD have elevated risk of depression and anxiety disorders after childbirth

Swedish nationwide population study finds mothers with ADHD have elevated risk of depression and anxiety disorders after childbirth

In the general population, most mothers experience mood disturbances right after childbirth, commonly known as postpartum blues, baby blues, or maternity blues. Yet only about one in six develop symptoms with a duration and magnitude that require treatment for depressive disorder, and one in ten for anxiety disorder.

To what extent does ADHD contribute to the risk of such disorders following childbirth? A Swedish study team used the country’s single-payer health insurance database and other national registers to conduct the first nationwide population study to explore this question.

They used the medical birth register to identify all 420,513 women above 15 years of age who gave birth to their first child, and all 352,534 who gave birth to their second child, between 2005 and 2013. They excluded miscarriages. They then looked for diagnoses of depression and/or anxiety disorders up to a year following childbirth.

In the study population, 3,515 mothers had been diagnosed with ADHD, and the other 769,532 had no such diagnosis. 

Following childbirth, depression disorders were five times more prevalent among mothers with ADHD than among their non-ADHD peers. Excluding individuals with a prior history of depression made little difference, lowering the prevalence ratio to just under 5. Among women under 25, the prevalence ratio was still above 3, while for those 25 and older it was above 6.

Similarly, anxiety disorders were over five times more prevalent among mothers with ADHD than among their non-ADHD peers. Once again, excluding individuals with a prior history of depression made little difference, lowering the prevalence ratio to just under 5. Among women under 25, the prevalence ratio was still above 3, while for those 25 and older it was above 6.

The team cautioned, “There is a potential risk of surveillance bias as women diagnosed with ADHD are more likely to have repeated visits to psychiatric care and might have an enhanced likelihood of also being diagnosed with depression and anxiety disorders postpartum, compared to women without ADHD.”

Nevertheless, they concluded, “ADHD is an important risk factor for both depression and anxiety disorders in the postpartum period and should be considered in the post- pregnancy maternal care, regardless of sociodemographic factors and the presence of other psychiatric disorders. Parental education prior to conception, psychological surveillance during, and social support after childbirth should be provided to women diagnosed with ADHD.”

December 22, 2023

Meta-analysis suggests acupuncture might offer effective treatment for ADHD, but suffers from methodological flaws

Meta-analysis suggests acupuncture might offer effective treatment for ADHD, but suffers from methodological flaws

Noting that previous “systematic reviews concluded that currently available data on the clinical effectiveness of acupuncture for treating ADHD are yet to be sufficient to support its routine use,” a South Korean study team conducted an updated systematic search of the medical literature for randomized controlled trials (RCTs) comparing acupuncture with drug treatment for children and adolescents with ADHD. There were no restrictions on language or publication type.

Only two of the meta-analyses involved more than two RCTs. 

One of them, of six RCTs with a combined 541 participants, reported total treatment efficacy of acupuncture to be at least equal to that of conventional treatment with ADHD medicines. 

Another, of five RCTs with a total of 351 participants, reported total treatment efficacy of combined acupuncture and ADHD drugs to be at least equal to that of conventional treatment with ADHD medicines.

Two RCTs with a Noting that previous “systematic reviews concluded that currently available data on the clinical effectiveness of acupuncture for treating ADHD are yet to be sufficient to support its routine use,” a South Korean study team conducted an updated systematic search of the medical literature for randomized controlled trials (RCTs) comparing acupuncture with drug treatment for children and adolescents with ADHD. There were no restrictions on language or publication type.

Only two of the meta-analyses involved more than two RCTs. 

One of them, of six RCTs with a combined 541 participants, reported total treatment efficacy of acupuncture to be at least equal to that of conventional treatment with ADHD medicines. 

Another, of five RCTs with a total of 351 participants, reported total treatment efficacy of combined acupuncture and ADHD drugs to be at least equal to that of conventional treatment with ADHD medicines.

Two RCTs with a combined 152 participants reported a large effect size improvement in hyperactivity/impulsivity symptoms from acupuncture treatment versus conventional drug treatment.

From this one could superficially conclude that acupuncture is at least as effective for treating ADHD as the medicines currently considered to be the standard of care, and that there is no need to combine acupuncture with drug treatment.

However, there were numerous methodological shortcomings:

  • No effort was made to look for publication bias.
  • There were few RCTs, and the combined number of participants was relatively small.
  • Only one of the six RCTs in the first meta-analysis and none of the five RCTs in the second meta-analysis was rated “low risk of bias.”
  • Though nowhere stated in the journal article, there may have been cultural bias as well. All studies included in the meta-analyses were conducted in China. As China has emerged as a global superpower, it has been eager to portray its traditional medicine as at least equal if not superior to forms of medicine originating elsewhere.
  • The authors noted, “the quality of the studies included in this systematic review was poor. Assessing the blinding of studies is a major aspect in determining the risk of bias of a study, but most of the studies did not provide any relevant information.” 

The authors concluded, “The current evidence on AT [acupuncture treatment] is still too limited to support its routine use in treating ADHD.”

152 participants reported a large effect size improvement in hyperactivity/impulsivity symptoms from acupuncture treatment versus conventional drug treatment.

From this one could superficially conclude that acupuncture is at least as effective for treating ADHD as the medicines currently considered to be the standard of care, and furthermore that there is no need to combine acupuncture with drug treatment.

However, there were numerous methodological shortcomings:

  • No effort was made to look for publication bias.
  • There were few RCTs, and the combined number of participants was relatively small.
  • Only one of the six RCTs in the first meta-analysis and none of the five RCTs in the second meta-analysis was rated “low risk of bias.”
  • Though nowhere stated in the journal article, there may have been cultural bias as well. All studies included in the meta-analyses were conducted in China. As China has emerged as a global superpower, it has been eager to portray its traditional medicine as at least equal if not superior to forms of medicine originating elsewhere.
  • The authors noted, “the quality of the studies included in this systematic review was poor. Assessing the blinding of studies is a major aspect in determining the risk of bias of a study, but most of the studies did not provide any relevant information.” 

The authors concluded, “The current evidence on AT [acupuncture treatment] is still too limited to support its routine use in treating ADHD.”

January 4, 2024