September 13, 2024

Swedish Population Study Suggests Stimulants Reduce Hospitalization and Suicidality, Have No Significant Effect on Work Disability

A meta-analysis of short-term, placebo-controlled, randomized clinical trials (Cortese et al. 2018), looking at both efficacy and safety, supported prescribing stimulants – methylphenidate use in children and adolescents and amphetamine use in adults – as first-choice medications. 

However, these were short-term studies, and they focused on relieving ADHD symptoms. What about longer-term outcomes, especially looking more broadly at functional impairment and overall quality of life? 

Sweden has a single-payer health insurance system that encompasses virtually every resident and is linked to national registers that enable researchers to conduct nationwide population studies. 

A joint Finnish-Swedish research team used Sweden’s registers to study outcomes for all individuals of working age, 16 to 65 years old, living in Sweden who had received a diagnosis of ADHD from 2006 through 2021. The resulting study cohort encompassed 221,714 persons with ADHD. 

The team adjusted for the following confounding variables: Genetics, baseline severity of symptoms, baseline comorbidities, temporal order of treatments (which medication was used as first, second, third, and so forth, including also nonuse of ADHD medications), time since cohort entry, and time-varying use of psychotropic drugs, including antidepressants, anxiolytics, hypnotics, mood stabilizers (carbamazepine, valproic acid, and lamotrigine), lithium, antipsychotics, and drugs for addictive disorders. 

With these adjustments, they discovered that amphetamine treatment was associated with a roughly 25% reduction in psychiatric hospitalization relative to unmedicated ADHD. Lisdexamphetamine was associated with a roughly 20% reduction, dexamphetamine with a 12% reduction, and methylphenidate with a 7% reduction. All four medications are stimulants

None of the non-stimulant medications – atomoxetine, guanfacine, clonidine – had any significant effect on psychiatric hospitalization. Nor did modafinil a drug that is not FDA approved for ADHD but is sometimes used when other drugs fail. 

Amphetamine was also associated with the greatest reduction in suicide attempts or deaths, with a roughly 40% decline relative to unmedicated ADHD. Dexamphetamine was associated with a roughly 30% decline and lisdexamphetamine with a roughly 25% decline. The stimulant methylphenidate was only associated with an 8% reduction, and modafinil had no significant effect. 

Surprisingly, non-stimulant medications were associated with significant increases in suicide attempts or deaths: 20% for atomoxetine, 65% for guanfacine, and almost double for clonidine

Amphetamine and lisdexamphetamine also reduced the risk of nonpsychiatric hospitalization by more than a third compared to unmedicated ADHD. Dexamphetamine was associated with a risk reduction of more than 25%, methylphenidate with 20% lesser risk.  

The non-stimulant atomoxetine was associated with a roughly 15% reduction in risk of nonpsychiatric hospitalization. But neither guanfacine nor clonidine had any significant effect. 

Turning to work disability, atomoxetine was the only ADHD medication associated with a reduction – a roughly 10% improvement. All other medications had no significant effect

The team concluded, “In this cohort study of adolescents and adults with ADHD, the use of medications for ADHD, especially lisdexamphetamine and other stimulants, was associated with decreased risk of psychiatric hospitalizations, suicidal behavior, and nonpsychiatric hospitalizations during periods when they were used compared with periods when ADHD medication was not used. Non-stimulant atomoxetine use was associated with decreased risk of work disability.” 

Heidi Taipale, Jakob Bergström, Katalin Gèmes, Antti Tanskanen, Lisa Ekselius, Ellenor Mittendorfer-Rutz, and Magnus Helgesson, “Attention-Deficit/Hyperactivity Disorder Medications and Work Disability and Mental Health Outcomes,” JAMA Network Open (2024), 7(3):e242859, https://doi.org/10.1001/jamanetworkopen.2024.2859

Cortese S, Adamo N, Del Giovane C, et al., “Comparative efficacy and tolerability of medications for attention- deficit hyperactivity disorder in children, adolescents, and adults: a systematic review and network meta-analysis,” Lancet Psychiatry (2018) 5(9):727-738, https://doi.org/10.1016/S2215-0366(18)30269-4

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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

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

Does ADHD Medication Improve the Parenting Skills of Adults with ADHD?

Does ADHD Medication Improve the Parenting Skills of Adults with ADHD?

Raising children is not easy. I should know.

As a clinical psychologist, I've helped parents learn the skills they need to be better parents. And my experience raising three children confirmed my clinical experience.

Parenting is a tough job under the best of circumstances, but it is even harder if the parent has ADHD.

For example, an effective parent establishes rules and enforces them systematically. This requires attention to detail, self-control, and good organizational skills. Given these requirements, it is easy to see how ADHD symptoms interfere with parenting. These observations have led some of my colleagues to test the theory that treating ADHD adults with medication would improve their parenting skills. I know about two studies that tested this idea.

In 2008, Dr. Chronis-Toscano and colleagues published a study using a sustained-release form of methylphenidate for mothers with ADHD. As expected, the medication decreased their symptoms of inattention and hyperactivity/impulsivity. The medication also reduced the mother's use of inconsistent discipline and corporal punishment and improved their monitoring and supervision of their children.

In a 2014 study, Waxmonsky and colleagues observed ADHD adults and their children in a laboratory setting once when the adults were off medication and once when they were on medication. They used the same sustained-release form of amphetamine for all the patients. As expected, the medications reduced ADHD symptoms in the parents. This laboratory study is especially informative because the researchers made objective ratings of parent-child interactions, rather than relying on the parents' reports of those interactions. Twenty parents completed the study. The medication led to less negative talk and commands and more praise by parents. It also reduced negative and inappropriate behaviors in their children.

Both studies suggest that treating ADHD adults with medication will improve their parenting skills. That is good news. But they also found that not all parenting behaviors improved. That makes sense. Parenting is a skill that must be learned. Because ADHD interferes with learning, parents with the disorder need time to learn these skills. Medication can eliminate some of the worst behaviors, but doctors should also provide adjunct behavioral or cognitive-behavioral therapies that could help ADHD parents learn parenting skills and achieve their full potential as parents.

May 7, 2021

Study Finds Association Between Childhood ADHD and Poor Dental Health

The Spanish National Health Survey tracks health care outcomes through representative samples of the Spanish population. 

A Spanish research team used survey data to explore the relationship between ADHD symptoms and dental and gum health in a representative sample of 3,402 Spanish children aged 6 to 14.

While previous studies have found associations between ADHD and poor dental health, they have not fully accounted for such important determinants of poor oral health as socioeconomic status, dental hygiene, or diet. 

The team therefore adjusted for sociodemographic factors, lifestyle variables, and oral hygiene behaviors. More specifically, they adjusted for sex, age, social class, parental education, exposure to tobacco smoke, consumption of sweets, consumption of sugary drinks, use of asthma or allergy medication, adequate oral hygiene behavior of children, adherence to regular dental visits, parental adequate oral hygiene behavior, and parental adherence to regular dental visits.

With those adjustments, children with ADHD symptoms had over twice the incidence of dental caries (cavities) as their counterparts without ADHD symptoms.

Tooth extractions and dental restorations also occurred with over 40% greater frequency in children with ADHD symptoms.

Gum bleeding, a sign of gum disease, was more than 60% more common among children with ADHD symptoms than among their non-ADHD peers.

Importantly, excluding children with daily sugar consumption, which left 1,693 children in the sample, made no difference in the outcome for cavities.

Excluding children with poor oral hygiene habits, which left 1,657 children in the sample, those with ADHD had 2.5-fold more caries than their non-ADHD counterparts.

Excluding children of low social class, which left 1,827 children in the sample, those with ADHD had 2.6-fold more caries than their non-ADHD counterparts.

Turning to a different method to address potential confounding factors, the team used nearest-neighbor propensity score matching to create virtual controls. This compared 461 children with ADHD to 461 carefully matched children without ADHD.

This time, children with ADHD symptoms had just under twice the incidence of cavities as their counterparts without ADHD symptoms, but 60% more tooth extractions and about 75% more dental restorations. The difference in gum bleeding became nonsignificant.

Noting that “The increased risk of caries was maintained when the analyses were restricted to middle/high social class families and children with low sugar intake, good oral hygiene behaviors and regular dental visits,” the team concluded, “Children with ADHD symptoms in Spain had worse oral health indicators than those without ADHD symptoms. Our results suggest that the association of ADHD symptoms with caries was independent of socioeconomic level, cariogenic diet, frequency of toothbrushing, and dental visits.”

June 13, 2025

A Lesson in Correlation Versus Causation : Maternal Smoking and ADHD Risk in Children

Meta-analysis Finds Strong Link Between Maternal Smoking During Pregnancy and Increased Risk of ADHD in Children

This new meta-analysis confirms what other meta-analysis have already shown, i.e, that there exists in the population an association between maternal smoking during pregnancy and ADHD in their offspring.  But reader beware, association does not mean causation.

The team identified 55 studies with quantitative data suitable for meta-analysis, including 11 case-control, 13 cross-sectional, and 31 retrospective/prospective cohort studies. 

Altogether they combined more than four million persons in countries spanning six continents, including the United States, Finland, Sweden, Brazil, the Netherlands, Japan, the UK, Spain, China, Australia, New Zealand, Norway, Canada, France, Sweden, South Korea, Turkey, Romania, Bulgaria, Lithuania, Germany, Denmark, Egypt, and India.

Meta-analysis of all 55 studies found that offspring of mothers who smoked tobacco during pregnancy were about 70% more likely to develop ADHD than offspring of mothers who did not smoke during pregnancy.

Because variation in outcomes across studies was very high, the team performed subgroup analyses to explore potential sources of this heterogeneity. 

Comparing study designs, cohort studies reported roughly 50% greater odds of ADHD among children of mothers who smoked during pregnancy, whereas case-control studies reported roughly 70% greater odds and cross-sectional studies 2.3-fold greater odds.

Studies using the most reliable method of determining ADHD – clinical interview/professional diagnosis – reported 90% greater odds, contrasting with 66% through medical records/databases and 58% through self-report by child/parent or through teacher report.

Good quality studies reported roughly 75% greater odds. 

Studies with sample sizes above two thousand similarly found 70% greater odds.

There was no sign of publication bias using the more commonly used Egger’s test, but a marginal indication of publication bias using Begg’s test. Performing a standard correction reduced the effect size, indicating that the offspring of mothers who smoked tobacco during pregnancy were over 50% more likely to develop ADHD than the offspring of mothers who did not smoke during pregnancy.

The team concluded, “This systematic review and meta-analysis of 55 studies, encompassing over four million participants, provides compelling evidence that maternal tobacco smoking during pregnancy significantly increases the odds of ADHD in children … These findings underscore the critical need for public health interventions aimed at reducing tobacco smoking during pregnancy.”

However, we disagree with this conclusion; The authors ignore substantial evidence showing that maternal smoking during pregnancy is confounded by maternal ADHD. These mothers transmit ADHD via genetics, not via their smoking. This study should be seen not as "...[further evidence that smoking during pregnancy causes ADHD.] ", but as a lesson in how easy it can be to see correlation as causation.

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June 10, 2025

Meta-analysis Finds Little Evidence of Efficacy for Animal-Assisted Interventions for Treating Childhood ADHD

Study Background:

Animal-assisted interventions (AAIs) involve structured interactions with animals, designed and carried out by mental health teams assisted by trained human–animal professionals, to achieve specific therapeutic or educational goals. While a wide variety of animals may be used, horses and dogs tend to predominate. These interventions often involve physical contact, imitation, and play aimed at reducing stress and generating affection. Previous research has suggested that AAI to those with a range of developmental and mental health conditions.

Just how effective are they for treating ADHD in children and adolescents? Recent years have seen an increase in studies into AAIs for children with ADHD, but previous systematic reviews have not included quantitative meta-analysis to evaluate efficacy.

The Study:

A Chinese study team based in Nanjing set out to remedy that with a systematic search of the peer-reviewed published medical literature aimed at performing meta-analyses of efficacy.

The team limited its search to randomized controlled trials (RCTs) and pre–post single-group studies involving children and adolescents diagnosed with ADHD.

Meta-analysis of five studies with a combined total of 95 participants reported no significant effect of AAIs on ADHD symptom severity. There was negligible variation (heterogeneity) in outcomes among the studies.

Similarly, meta-analysis of the six studies encompassing 323 individuals found no significant improvements in social behavior. There was no heterogeneity and no sign of publication bias. Breaking that down into subcategories of social interaction (4 studies, 190 persons), social skill (3 studies, 53 persons), and problem behavior (4 studies, 80 participants) made no difference.

Likewise, meta-analysis of the three studies encompassing 61 individuals found no significant improvements in emotional control. Again, there was no heterogeneity and no sign of publication bias.

Three studies combining 56 participants reported no significant reductions in anxiety and depression, again with no heterogeneity and no sign of publication bias.

However, meta-analyses of five studies encompassing 194 individuals found a medium effect size association between AAIs and declines in attention problems, and a medium-to-large effect size improvement in learning and cognition. Heterogeneity was negligible to low.

Finally, meta-analysis of three studies combining 95 participants reported a large effect size improvement in motor proficiency, with moderate heterogeneity.

The Conclusion:

The team concluded, “As an ADHD management strategy complementary to gold-standard approaches, such as medication or multimodal interventions, AAIs did not appear to be more effective in improving the majority of core ADHD outcomes in children. Future studies should incorporate rigorous study designs with large sample sizes and a standard protocol to achieve more valid and reliable conclusions.”

June 5, 2025