August 12, 2024

Meta-analysis Finds Quality of Life Improvements Associated with ADHD Medications

Quality of life (QoL) is defined as a person’s satisfaction with their life, measured across several dimensions including psychological, social, health, biological, and economic well-being. For adults, these are usually self-reported. QoL for children and adolescents is usually reported by parents.  

Medications for ADHD include stimulants (methylphenidate and amphetamines) and non-stimulants (e.g., atomoxetine, clonidine, guanfacine, viloxazine). As QoL is related to ADHD symptoms’ severity, management of ADHD via medication could improve not only core symptoms but also QoL in people with ADHD.  

Noting the absence of meta-analytic evidence on the effects of ADHD medications on QoL, an international research team conducted a systematic review and meta-analysis of parallel or cross-over randomized clinical trials (RCTs) to estimate the effects of ADHD medication on QoL. They also performed secondary analyses to see if these effects differed in children and adolescents versus adults, as well as by class of medications, and if they were moderated by length of treatment. 

Meta-analyses of four RCTs with a combined total of 950 participants with ADHD (45% adults) found a medium effect size improvement among those receiving amphetamines by comparison with those receiving placebo. There was no sign of publication bias, but there was wide variation (heterogeneity) in effect size estimated among the studies.  

Meta-analysis of four RCTs with a combined total of 1,094 participants with ADHD (57% adults) found a small-to-medium effect size improvement among those receiving methylphenidate by comparison with those receiving placebo. Again, there was no sign of publication bias, but wide variation in effect sizes among the studies. 

Due to lack of sufficient data, the team could not explore whether length of treatment affected the results, or if there were differences between children/adolescents and adults. 

Finally, a meta-analysis of eleven RCTs with a combined total of 3,344 participants with ADHD (63% adults) likewise found a small effect size improvement among those taking atomoxetine compared with those receiving placebo. Once again, there was no sign of publication bias, but wide variation in effect sizes among the studies. 

The team was able to establish that for atomoxetine treatment, length of intervention – the studies ranged from 6 to 24 weeks – had no significant moderating effect. Similarly, they found no significant differences in effect on children and adolescents versus adults.  

A single RCT evaluating modafinil treatment in adults found no improvements at any dose, whereas a single RCT testing non-stimulant guanfacine reported a medium effect size improvement in QoL.  Modafinil is not FDA approved for ADHD but is sometimes used as a last resort if other treatments fail.

The team concluded that the FDA approved medications for ADHD were significantly more efficacious than placebo in improving QoL in people with ADHD.  The improvements in Q0L were, however, smaller than what has been found for improvements is the symptoms of ADHD (inattention, hyperactivity, impulsivity).  More work is needed to detect differences by age and length of treatment. 

Alessio Bellato, Nadia J. Perrott, Lucia Marzulli, Valeria Parlatini, David Coghill, and Samuele Cortese, “Systematic Review and Meta-Analysis: Effects of Pharmacological Treatment for Attention-Deficit/Hyperactivity Disorder on Quality of Life,” Journal of the American Academy of Child & Adolescent Psychiatry (2024), https://doi.org/10.1016/j.jaac.2024.05.023

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ADHD medication and risk of suicide

ADHD medication and risk of suicide

A Chinese research team performed two types of meta-analyses to compare the risk of suicide for ADHD patients taking ADHD medication as opposed to those not taking medication.

The first type of meta-analysis combined six large population studies with a total of over 4.7 million participants. These were located on three continents - Europe, Asia, and North America - and more specifically Sweden, England, Taiwan, and the United States.

The risk of suicide among those taking medication was found to be about a quarter less than for unmediated individuals, though the results were barely significant at the 95 percent confidence level (p = 0.49, just a sliver below the p = 0.5 cutoff point). There were no significant differences between males and females, except that looking only at males or females reduced sample size and made results non-significant.

Differentiating between patients receiving stimulant and non-stimulant medications produced divergent outcomes. A meta-analysis of four population studies covering almost 900,000 individuals found stimulant medications to be associated with a 28 percent reduced risk of suicide. On the other hand, a meta-analysis of three studies with over 62,000 individuals found no significant difference in suicide risk for non-stimulant medications. The benefit, therefore, seems limited to stimulant medication.

The second type of meta-analysis combined three within-individual studies with over 3.9 million persons in the United States, China, and Sweden. The risk of suicide among those taking medication was found to be almost a third less than for unmediated individuals, though the results were again barely significant at the 95 percent confidence level (p =0.49, just a sliver below the p = 0.5 cutoff point). Once again, there were no significant differences between males and females, except that looking only at males or females reduced the sample size and made results non-significant.

Differentiating between patients receiving stimulant and non-stimulant medications once again produced divergent outcomes. Meta-analysis of the same three studies found a 25 percent reduced risk of suicide among those taking stimulant medications. But as in the population studies, a meta-analysis of two studies with over 3.9 million persons found no reduction in risk among those taking non-stimulant medications.

A further meta-analysis of two studies with 3.9 million persons found no reduction in suicide risk among persons taking ADHD medications for 90 days or less, "revealing the importance of duration and adherence to medication in all individuals prescribed stimulants for ADHD."

The authors concluded, "exposure to non-stimulants is not associated with a higher risk of suicide attempts. However, a lower risk of suicide attempts was observed for stimulant drugs. However, the results must be interpreted with caution due to the evidence of heterogeneity ..."

December 13, 2021

How Effective and Safe are Stimulant Medications for Older Adults?

How effective and safe are stimulant medications for older adults?

Older adults are at greater risk for cardiovascular disease. Psychostimulants may contribute to that risk through side effects, such as elevation of systolic blood pressure, diastolic blood pressure, and heart rate.

On the other hand, smoking, substance abuse, obesity, and chronic sleep loss - all of which are associated with ADHD - are known to increase cardiovascular risk, and stimulant medications are an effective treatment for ADHD.

So how does this all shake out? A Dutch team of researchers sets out to explore this. Using electronic health records, they compared all 139 patients 55 years and older at PsyQ outpatient clinic, Program Adult ADHD, in The Hague. Because a principal aim of the study was to evaluate the effect of medication on cardiovascular functioning after first medication use, the 26 patients who had previously been prescribed ADHD medication were excluded from the study, leaving a sample size of 113.

The ages of participants ranged from 55 from 79, with a mean of 61. Slightly over half were women. At the outset, 13 percent had elevated systolic and/or diastolic blood pressure, 2 percent had an irregular heart rate, 15 percent had an abnormal electrocardiogram, and 29 percent had some combination of these (a "cardiovascular risk profile"), and 21 percent used antihypertensive medication.

Three out of four participants had at least e comorbid disorder. The most common are sleep disorders, affecting a quarter of participants, and unipolar mood disorders (depressive or more rarely manic episodes, but not both), also affecting a quarter of participants.

Twenty-four patients did not initiate pharmacological treatment. Of the 89 who received ADHD medication, 58 (65%) reported positive effects, and five experienced no effect. Thirty-eight (43%) discontinued ADHD medication while at the clinic due to lack of effect or to side effects. The most commonly reported positive effects were enhanced concentration, more overview, less restlessness, more stable mood, and having more energy. The principal reasons for discontinuing medication were anxiety/depression, cardiovascular complaints, and lack of effect.

Methylphenidate raised heart rate and lowered weight, but had no significant effect on systolic and diastolic blood pressure. Moreover, there was no significant correlation between methylphenidate dosage and any of these variables, nor between methylphenidate users taking hypertensive medication and those not taking such medication. There was no significant difference in systolic or diastolic blood pressure and heart rate before and after the use of methylphenidate among patients with the cardiovascular risk profiles.

Systolic blood pressure rose in ten out of 64 patients, with two experiencing an increase of at least 20 mmHg. It descended in five patients, with three having a decrease of at least 20 mmHg. Diastolic blood pressure rose by at least 10 mmHg in four patients, while dropping at least 10 mmHg in five others.

The authors concluded "that the use of a low dose of ADHD-medication is well tolerated and does not cause clinically significant cardiovascular changes among older adults with ADHD, even among those with an increased cardiovascular risk profile. Furthermore, our older patients experienced significant and clinically relevant improvement of their ADHD symptoms using stimulants, comparable with what is found among the younger age group," and that "the use of methylphenidate may be a relatively safe and effective treatment for older adults with ADHD, under the condition that all somatic complaints and especially cardiovascular parameters are monitored before and during pharmacological treatment."

Yet they cautioned that "due to the observational nature of the study and the lack of a control group, no firm conclusions can be drawn as to the effectiveness of the stimulants used. ... Important factors that were not systematically reported were the presence of other risk factors, such as smoking, substance (ab)use, aspirin use, and level of physical activity. In addition, the response to medication was not systematically measured"

December 21, 2021

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

Meta-analysis Suggests Physical Activity Improves Attention in Schoolchildren with ADHD

Background: 

Noting that “Previous research has demonstrated that attention significantly influences various domains such as language, literacy, and mathematics, making it a crucial determinant of academic achievement,” an international study team performed a comprehensive search of the peer-reviewed medical literature for studies evaluating effects of physical activity on attention. 

The Study:

The team’s meta-analysis of ten studies with a combined total of 474 participants found moderate reductions in attention problems following physical activity. They found no significant evidence of publication bias, but there was considerable variation in outcomes between studies (heterogeneity). 

To tease out the reasons for this variability, the team looked at specific attributes of the physical activity regimens used in the studies. 

The seven studies with 168 participants that involved mentally engaging physical activity reported large reductions in attention problems, whereas the three studies with 306 persons that used aerobic exercise found no reduction whatsoever. Heterogeneity in the former was reduced, in the latter all but disappearing. 

Comparing studies with other interventions as control groups (6 studies, 393 participants) with those with no intervention as control (4 studies, 81 participants), the former reported only small improvements in attention problems, while the latter reported large improvements. 

Duration of physical activity made little difference. The four studies with physical activity of an hour or more reported better outcomes than the six with less than an hour, but the difference was not significant. 

Greater frequency did make a difference, but in a counterintuitive way. The seven studies with one or two physical activity interventions per week (162 participants) reported large reductions in attention problems, whereas the three studies with three or more interventions per week (312 participants) showed no improvement. 

Conclusion:

The authors concluded, “Our study suggests that cognitively engaging exercise is more effective in improving attention problems in school-aged children with ADHD.” Moreover, “the benefits of improved attention in school-age children with ADHD are not necessarily positively correlated with higher frequency and longer duration of physical activity.”  Also keep in mind that exercise, while important for all children, should not replace medical and psychological treatments for the disorder.

March 10, 2025

Updated Analysis of ADHD Prevalence in The United States

The National Health Interview Survey (NHIS) is conducted annually by the National Center for Health Statistics at the Centers for Disease Control and Prevention. The NHIS is done primarily through face-to-face computer-assisted interviews in the homes of respondents. But telephone interviews are substituted on request, or where travel distances make in-home visits impractical.  

For each interviewed family, only one sample child is randomly selected by a computer program.  

The total number of households with a child or adolescent aged 3-17 for the years 2018 through 2021 was 26,422. 

Based on responses from family members, 9.5% of the children and adolescents randomly surveyed throughout the United States had ADHD.  

This proportion varied significantly based on age, rising from 1.5% for ages 3-5 to 9.6% for ages 6-11 and to 13.4% for ages 12-17. 

There was an almost two-to-one gap between the 12.4% prevalence among males and the 6.6% prevalence among females. 

There was significant variation by race/ethnicity. While rates among non-Hispanic whites (11.1%) and non-Hispanic blacks (10.5%) did not differ significantly, these two groups differed significantly from Hispanics (7.2%) and Others (6.6%). 

There were no significant variations in ADHD prevalence based on highest education level of family members. 

But family income had a significant relationship with ADHD prevalence, especially at lower incomes. For family incomes under the poverty line, the prevalence was 12.7%. That dropped to 10.3% for family incomes above the poverty level but less than twice that level. For all others it dropped further to about 8.5%. Although that might seem like poverty causes ADHD, we cannot draw that conclusion.  Other data indicate that adults with ADHD have lower incomes.  That would lead to more ADHD in kids from lower income families.

There was also significant geographic variation in reported prevalence rates. It was highest in the South, at 11.3%, then the Midwest at 10%, the Northeast at 9.1%, with a jump down to 6.9% in the West. 

Overall ADHD prevalence did not vary significantly by year over the four years covered by this study. 

Study Conclusion:

This study highlights a consistently high prevalence of developmental disabilities among U.S. children and adolescents, with notable increases in other developmental delays and co-occurring learning and intellectual disabilities from 2018 to 2021. While the overall prevalence remained stable, these findings emphasize the need for continued research into potential risk factors and targeted interventions to address developmental challenges in youth.

It is also important to note that this study assessed the prevalence of ADHD being diagnosed by healthcare professionals.  Due to variations in healthcare accessibility across the country, the true prevalence of ADHD may differ still.

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March 7, 2025

Study Finds ADHD Associated With Sleep Issues, but Reports Improvement with Medication

Large U.S. Cohort Study Finds ADHD Associated With Sleep Insufficiency and Bedtime Irregularity, but Reports Improvement with ADHD Medication

Background:

An international research team used the nationally representative 2020–2021 U.S. Survey of Children’s Health to explore associations between ADHD, weeknight sleep insufficiency, and bedtime irregularity. 

"Sleep sufficiency" refers to the recommended amount of sleep for an individual. Sleep recommendations vary by age and other factors, such as health and lifestyle. For example, 7-9 hours is typically considered sufficient sleep for most adults, but an active teen may require closer to 10 hours of sleep per day.

Previous studies have shown that issues with both falling and staying asleep are common in individuals with ADHD.

The Study:

The team matched 7,671 children and adolescents with ADHD aged 3-17 to 51,572 controls.  

Noting that “The few available population-based studies examining sleep in children with ADHD have focused on circumscribed age ranges, limiting generalizability across childhood, and have seldom included controls,” and “bedtime irregularity has received limited empirical attention in children with ADHD,” this study focused on these aspects of sleep impairment. 

The study group excluded children and adolescents with ADHD with Down syndrome, current or lifetime cerebral palsy, and current or lifetime intellectual disability. In the control group, it excluded individuals with Down syndrome, cerebral palsy, intellectual disability, speech and language disorder, autism spectrum disorder, ADHD, anxiety, depression, behavioral or conduct problems, Tourette syndrome, and use of mental health services in the preceding 12 months. These groups were excluded to limit potential confounding factors.

After adjustment for covariates, parents of children and adolescents with ADHD reported weekday sleep insufficiency 65% more frequently than parents of controls.  

However, when comparing matched controls with children and adolescents with ADHD who were being treated with ADHD medication, there was no significant difference. 

Similarly, there was a small but significant effect size increase in bedtime irregularity among children and adolescents with ADHD relative to their matched controls. 

Yet there was also a small but significant effect size decrease in bedtime irregularity among those taking medication for ADHD relative to those who were unmedicated. 

The team noted, “Interestingly, here, ADHD medication use was linked to less bedtime irregularity across full and age-stratified samples, and not related to sleep insufficiency. However, research indicates the association between stimulant use and sleep problems is attenuated with longer duration of use, and also suggests the potential for stimulants to produce positive effects on sleep through reduced bedtime resistance. Further, ADHD medication type, not specified, may have influenced outcomes.” 

The Take-Away:

The study concluded that ADHD in children was linked to insufficient sleep and irregular bedtimes in a nationally representative sample, reinforcing and expanding previous research. The findings emphasize the influence of various factors on sleep insufficiency and bedtime irregularity, including race, screen time, poverty, ADHD severity, and depression.

February 28, 2025