April 24, 2024

Large Six-region Meta-analysis Finds No Association Between ADHD Medications and Cardiovascular Risk

Are attention-deficit/hyperactivity disorder (ADHD) medications associated with risk of cardiovascular disease (CVD)?

An international study team has just explored this question with a meta-analysis of nineteen studies with a total of almost four million participants of all ages. It included 3,931,532 participants from six countries or regions: United States, South Korea, Canada, Denmark, Spain, and Hong Kong. 

Overall, using the entire data set, it found no significant association between any ADHD medication use and any cardiovascular event. 

The same held true when breaking this down by children and adolescents (twelve studies with over 1.7 million participants), young and middle-aged adults (seven studies with over 850,000 participants), and older adults (six studies with over a quarter million participants).

The team then compared the data for stimulant medications with data for non-stimulant medications. A meta-analysis of 17 studies with over 3.8 million participants found no significant association between stimulant medications and cardiovascular risk. Similarly, a meta-analysis of three studies with over 670,000 participants found no significant association between non-stimulant medications and cardiovascular risk.

Distinguishing between types of cardiovascular risk made no difference. For instance, a meta-analysis of nine studies with over 900,000 participants found no effect of stimulant medications on risk of myocardial infarction (heart attack), and a meta-analysis of six studies, also with over 900,000 participants, found no effect of stimulant medications on risk of cerebrovascular disease, including stroke, brain aneurysm, brain bleed, and carotid artery disease. A meta-analysis of eight studies with over 1.1 million participants did find an increase in the occurrence of cardiac arrest and tachyarrhythmias (racing heart rate accompanied by arrhythmias), but it was not statistically significant.

A meta-analysis of eleven studies with over 3.1 million persons with no prior history of cardiovascular disease found absolutely no effect of ADHD medications on subsequent risk for any cardiovascular event. Another meta-analysis, of eight studies encompassing over 1.8 million individuals with a prior history of cardiovascular disease, reported a higher rate of subsequent occurrence, but it was not considered statistically significant.

The team concluded, “Overall, our meta-analysis provides reassuring data on the putative cardiovascular risk with ADHD medications.” An international team of researchers recently investigated whether medications for attention-deficit/hyperactivity disorder (ADHD) are linked to an increased risk of cardiovascular disease (CVD). They conducted a comprehensive review, known as a meta-analysis, which included 19 studies with nearly four million participants from six countries or regions: the United States, South Korea, Canada, Denmark, Spain, and Hong Kong.

The findings from the entire data set showed no significant link between the use of any ADHD medications and the occurrence of cardiovascular events. This lack of association was consistent across all age groups: children and adolescents (12 studies with over 1.7 million participants), young and middle-aged adults (7 studies with over 850,000 participants), and older adults (6 studies with over 250,000 participants).

The researchers also compared the effects of stimulant medications against non-stimulant medications on cardiovascular risk. Both categories showed no significant risks in a meta-analysis of 17 studies with more than 3.8 million participants for stimulants, and three studies with over 670,000 participants for non-stimulants.

Further analysis differentiated between types of cardiovascular risks, such as myocardial infarction (heart attack) and cerebrovascular diseases (like stroke, brain aneurysm, and carotid artery disease). Again, stimulant medications showed no significant impact on these conditions in studies involving over 900,000 participants each. However, a review of eight studies with over 1.1 million participants suggested a slight increase in incidents of cardiac arrest and tachyarrhythmias (a racing heart rate with irregular rhythms), but these findings were not statistically significant.

Additionally, an analysis of 11 studies involving more than 3.1 million people without a prior history of cardiovascular disease found no effect of ADHD medications on the risk of developing cardiovascular events. Likewise, an analysis of eight studies with over 1.8 million individuals who had a history of cardiovascular disease showed a higher occurrence rate of events, but this increase was also not statistically significant.

Conclusion:

The conclusion of the research team was clear: the data is reassuring and does not suggest a substantial cardiovascular risk associated with ADHD medications. Keep in  mind that this reflects current standards of care.  Most guidelines call for monitoring of pulse and blood pressure during treatment so that adverse cardiovascular outcomes can be avoided.

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Le Zhang, Honghui Yao, Lin Li, Ebba Du Rietz, Pontus Andell, Miguel Garcia-Argibay, Brian M. D’Onofrio, Samuele Cortese, Henrik Larsson, Zheng Chang, “Risk of Cardiovascular Diseases Associated With Medications Used in Attention-Deficit/Hyperactivity Disorder: A Systematic Review and Meta-analysis,” JAMA Network Open (2022) 5(11), e2243597, https://doi.org/10.1001/jamanetworkopen.2022.43597.

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Study Suggests Certain ADHD Meds May Have Protective Effect On The Brain

Might methylphenidate have a protective effect on brain development?

Methylphenidate, a psychostimulant, is among the drugs most frequently prescribed to children with ADHD.

Using magnetic resonance imaging(MRI), studies have shown that as children mature, those with ADHD differ from controls in developing regionally thinner cortices (the folded outer layer of the cerebrum that is essential to rational thought) and smaller lower basal ganglia(structures linked to the thalamus in the base of the brain and involved in the coordination of movement). The cortical differences were found in the right medial frontal motor region, the left middle/inferior frontal gyrus, and the right posterior parieto-occipital region in children with ADHD who were not taking psychostimulants.

A Dutch/Norwegian team of researchers conducted a randomized, double-blind, placebo-controlled trial with 96 males recruited from Dutch clinical programs. 48 were boys aged 10-12 years, and 47 were men between the ages of 23 and 40. None had previously been on methylphenidate. There were no significant differences in baseline age, ADHD symptom severity, estimated intelligence quotient, the proportion of right-handedness, or region of interest brain characteristics between the placebo and medication groups.

The trial was carried out during the standard 17-week waiting list time for evaluation and treatment to begin so that those receiving a placebo during the trial would not ultimately be at a disadvantage. The same MRI scanner was used for all measurements, both before and after treatment.

Among the boys, the methylphenidate group showed increased thickness in the right medial cortex, while the placebo group showed cortical thinning. In adults, both groups showed cortical thinning. When converted into an estimated mean rate of change in cortical thickness for the right medial cortex, boys taking methylphenidate could expect to lose about 0.01 mm per year, versus about 0.14 mm for boys not on methylphenidate.

In the right posterior cortex, scans also showed reduced thinning in the methylphenidate treatment group, though to a lesser extent. But there was no reduced thinning in the left frontal cortex.

The authors noted several limitations. The sample size was small. Second, "because we did not detect significant relationships between changes in cortical [regions of interest] and changes in symptom severity, the functional significance remains uncertain." Third, the follow-up period was relatively short, not allowing any assessment of the longer-term effects of the medication. Fourth, the differences in effects on the three brain regions examined were uneven, contrary to what had been expected from previous studies. They recommended replication with larger groups and longer follow-ups.

February 11, 2022

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

Meta-analysis Finds ADHD Associated with Higher-Risk of Dementia

The Background:

Dementia is a rapidly growing public health problem affecting more than 50 million people worldwide. Nearly 10 million new cases are diagnosed each year, and that number is expected to almost triple by 2050. The most common form is Alzheimer’s disease, accounting for roughly 60–70% of cases, followed by vascular dementia at around 20%. Other types include dementia with Lewy bodies, Parkinson’s disease dementia, and frontotemporal dementia. While no cure exists, managing modifiable risk factors (such as high blood pressure, smoking, physical inactivity, and poorly controlled diabetes) can delay or slow both the onset and progression of the condition. 

Several studies have reported an elevated dementia risk among people with ADHD, and a number of mechanisms may explain this association. These include shared genetic or neurobiological vulnerabilities, reduced cognitive reserve (leaving the brain less resilient to age-related damage), and greater lifetime exposure to other established dementia risk factors. 

Earlier reviews explored the possible link between ADHD and dementia, but tended toward a broader scope (incorporating other neurodegenerative disorders or mixing study designs), which introduced substantial variability and precluded quantitative synthesis. The relevant research literature has also expanded considerably since those reviews appeared. 

The Study:

This meta-analysis restricted inclusion to case-control and cohort studies, yielding five that met the criteria. One was a case-control study with 400 participants; the other four were cohort studies collectively covering 3.7 million individuals, two retrospective and two prospective. 

The Results:

Pooling the four cohort studies, individuals with ADHD showed approximately two-and-a-half times the dementia risk of those without the diagnosis. There was no indication of publication bias. 

The Take-Away:

The authors concluded that ADHD is associated with a significantly increased risk of all-cause dementia in later life, while noting that its relationship to specific dementia subtypes remains less clear and warrants attention in future research. 

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October 8, 2026

Meta-analysis Finds Association Between Maternal Polycystic Ovary Syndrome (PCOS) and ADHD in Offspring

The Background:

Women with polycystic ovary syndrome (PCOS) themselves show higher rates of ADHD. Because ADHD is partly heritable (meaning genes contribute to the condition), some of the increased ADHD seen in children of mothers with PCOS could come from shared genetic factors. In other words, a mother’s and her child’s increased risk might sometimes reflect common genes rather than an effect of the pregnancy itself. 

Beyond genetics, growing evidence points to maternal metabolic problems during pregnancy as another important risk factor for neurodevelopmental outcomes. PCOS is one of these conditions and is considered both potentially modifiable (treatable or manageable) and biologically plausible as a contributor to risk. PCOS affects an estimated 5–10% of women of reproductive age worldwide and is characterized by signs such as hyperandrogenism (higher-than-normal levels of “male” hormones), insulin resistance (poorer ability to use the hormone insulin, which can affect blood sugar and metabolism), and chronic low-grade inflammation. 

However, studies to date have not all reached the same conclusions. Some research suggests the association between maternal PCOS and offspring ADHD is stronger for girls, while other studies did not analyze results by child sex. Methodological differences make it harder to draw clear conclusions. 

The Study:

It’s important to note that the studies included in this meta-analysis were observational (cohort studies and case-control studies). Observational studies can identify associations (that two things occur together) but cannot prove that one causes the other. A cohort study follows people over time, and a case-control study compares people with a condition to similar people without it. 

The pooled results came from six studies that together included almost 1.4 million mother–child pairs and that adjusted for confounders (other factors that might influence the result, such as maternal age or socioeconomic status). After statistical adjustment, children of mothers with PCOS had about 40% greater odds of ADHD than children of mothers without PCOS. The analysis reported no evidence of publication bias (no clear sign that only positive studies were published) and zero heterogeneity (the results were consistent across the studies). 

There was no meaningful difference in results between cohort and case-control studies, and the meta-analysis did not find a significant difference in the association when comparing male and female offspring. 

The Take-Away:

The research team concluded that this large-scale synthesis found an association between maternal PCOS and higher odds of ADHD and other neuropsychiatric conditions in children. They suggested that children born to mothers with PCOS may benefit from developmental monitoring to identify and address problems early, while emphasizing that causal relationships have not been established. They called for further studies to confirm these findings and to investigate the biological and environmental mechanisms that might explain the association. Indeed, because women with PCOS show higher rates of ADHD than other women, we need genetically informed research designs to see if the reported association is confounded.

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October 1, 2026

Large Cohort Study Finds Dose-Response Association Between Food Insecurity and ADHD

The Background:

Food insecurity is a widespread public‑health problem. Food insecurity refers to limited or uncertain access to enough safe, nutritious food. This term is used to describe households that sometimes or often can’t afford enough food or can only buy cheaper, less‑healthy options. 

In the United States, almost eleven million children and teens (14%) lived in food‑insecure households in 2019. By 2023, the share of households with food‑insecure children and adolescents was estimated to have risen to about 18%. 

Food insecurity is linked to worse physical health in children, including conditions like anemia (low red‑blood‑cell count), asthma, and delays in physical or mental development. It is also associated with problems in thinking and conduct (for example, aggressive behavior, anxiety, depression, and trouble concentrating or sitting still). 

Those thinking and behavior problems can look a lot like ADHD (persistent patterns of inattention, hyperactivity, and impulsivity. This can make it hard for clinicians to tell whether symptoms come from ADHD itself, from the stress of poverty and food insecurity, or a mix of both. That overlap can complicate diagnosis and sometimes lead to misdiagnosis. 

Smaller recent studies have looked at mental‑health links and found higher odds of ADHD and other mental‑health conditions among food‑insecure children aged 5–11 years. In one set of findings, moderate food insecurity was associated with 50% greater odds of an ADHD diagnosis and severe food insecurity with about 67% greater odds relative to food‑secure children. 

The Study:

Because many past studies looked at single risk factors or only measured symptom severity, fewer investigations have focused specifically on household food insecurity as it relates to actual ADHD diagnoses and how that might matter for care. To address that gap, researchers used multiple years (2016–2022) of data from the U.S. National Survey of Children’s Health (NSCH). This survey is designed to be nationally representative and asks parents about their child’s health, including whether a doctor or other clinician has diagnosed ADHD. 

The study included 232,571 children and adolescents (ages 3–17) and used statistical methods to adjust for other factors that could affect ADHD risk. Those factors included the child’s sex and race/ethnicity; the mother’s age; family income expressed as a percentage of the federal poverty level (a government measure used to classify income groups); the highest level of parent education; adverse childhood experiences (such as exposure to abuse, household substance use, or parental separation); birthweight (for example, low birthweight); and not getting enough sleep. Adjusting for these variables helps isolate the association between food insecurity and ADHD, though it cannot prove cause and effect. 

The Results:

In this large, nationally representative sample, the researchers found a clear dose–response relationship: as the level of household food insecurity increased, so did the odds of a child having a clinician‑diagnosed ADHD (as reported by parents). In other words, greater food insecurity was linked to a higher likelihood of ADHD. 

Compared with children in households that “could always afford to eat good, nutritious meals” (the reference group), the study found the following increases in odds of ADHD: children in households that “could always afford enough to eat but not always the kinds of food we should eat” had about 30% greater odds; children in households that sometimes “could not afford enough to eat” had about 55% greater odds; and children in households that often “could not afford enough to eat” had about 80% greater odds. (Saying “30% greater odds,” etc., means the odds were 1.30, 1.55, and 1.80 times those of the reference group, respectively — this describes a relative increase, not the absolute percentage of children with ADHD.) 

The Take-Away:

The authors conclude that household food insecurity was associated with higher odds of parent‑reported clinician‑diagnosed ADHD in a dose‑response pattern. They suggest that reducing food insecurity (for example, ,by improving access to nutritious food and combining nutritional supports with mental‑health care) may help lower ADHD risk or reduce symptoms in some children. Reducing food insecurity should be a priority for society, but it is premature to conclude it will reduce the risk for ADHD. We know that parents with ADHD are more likely to lose their jobs and have lower incomes compared to parents with ADHD.  That might create food insecurity for their children who we know are at high risk for ADHD from genetic studies.  

 

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