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July 8, 2025

Norwegian Population Study Finds ADHD Associated with Much Higher Odds of Contact with Child Welfare Services

Background:

This nationwide population study by a Norwegian team aimed to evaluate the relationship between ADHD and various types of child welfare services contacts over a long-term period of up to 18 years among children and adolescents aged 5 to 18 years diagnosed with ADHD, in comparison to the general population within the same age group. 

Norway has a single-payer national health insurance system that fully covers virtually the entirety of its population. In combination with a system of national population and health registers, this facilitates nationwide population studies, overcoming the limitations of relying on population sampling. 

Study:

The study population included all 8,051 children and adolescents aged 5 to 18 who were diagnosed with ADHD for the first time in the Norwegian Patient Registry between 2009 and 2011. 

The study also included a comparison sample of 75,184 children and adolescents aged 5–18 with no child welfare services contact during 2009–2011. 

The interventions delivered by child welfare services in Norway are largely divided into two primary categories: supportive intervention and out-of-home placement. 

Supportive interventions include improving parenting skills, promoting child development, providing supervision and control, facilitating cooperation with other services, assessments and treatments by other institutions, and offering housing support. 

Norway uses foster homes or child welfare institutions as a last resort. When supportive interventions fail to meet the child’s needs, the child welfare services can temporarily place the child in these facilities. If parents disagree, the county social welfare board decides based on a municipal request. 

The team adjusted for potential confounders: sex, age, parental socioeconomic status (father’s and mother’s education and income level), and marital status. 

Results:

With these adjustments, children and adolescents diagnosed with ADHD were over six times more likely to have any contact with child welfare services than their general population peers. This was equally true for males and females.  

Children and adolescents diagnosed with ADHD were also over six times more likely to receive supportive interventions from child welfare services. Again, there were no differences between males and females. 

Finally, children and adolescents diagnosed with ADHD were roughly seven times more likely to have an out-of-home placement than their general population peers. For males this rose to eight times more likely. 

Conclusion:

The team concluded, “This population-based study provides robust evidence of a higher rate and strong association between ADHD and contact with CWS [Child Welfare Service] compared to the general population in Norway.” 

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Safety of Long-term Methylphenidate Treatment of Adults with ADHD

Safety of long-term methylphenidate treatment of adults with ADHD

The Comparison of Methylphenidate and Psychotherapy in adult ADHD Study (COMPAS) was a prospective, randomized multicenter clinical trial, comparing methylphenidate (MPH) with placebo in combination with cognitive-behavioral group psychotherapy or (GPT) individual clinical management (CM), the latter two being active controls. This was a year-long trial.

The German study team randomly assigned 433 participants with adult ADHD to each of the four study groups. As this was a 2 x 2 matrix trial, each study group included both one pharmacological intervention (MPH or placebo) and one psychological intervention (GPT or CM).

GPT included mindfulness training, skills for stress management, emotion regulation, and time management as well as behavioral analyses. CM sessions focused on participants' current concerns and medication.

As is usual in such trials, the number of participants decreased throughout the study as some individuals dropped out. At 13 weeks, 337 participants were still taking their study medication.

Both MPH and placebo were started at 10 mg doses, then up-titrated depending on clinical response. After 13 weeks, the mean MPH dose had risen to 50 mg, and the mean dose of placebo to 58 mg.

Safety

Among those taking MPH, 96 percent of participants reported at least one adverse event. Among those on placebo, the equivalent figure was 88 percent.

The principal adverse events occurring significantly more frequently in the MPH group were decreased appetite (22 vs. 3.8 %), dry mouth (15 vs. 4.8 %), palpitations (13 vs. 3.3 %), gastrointestinal infection (11 vs. 4.8 %), agitation (11 vs. 3.3 %), restlessness (10 vs. 2.9 %), excessive sweating, rapid heartbeat, and weight decrease (all 6.3 vs. 1.9 %).

The only adverse event that occurred significantly more frequently in the placebo group was a temporary loss of consciousness caused by a fall in blood pressure (2.4 vs. 0%).

Serious adverse events were infrequent in both groups, affecting 7.3 percent of those in the MPH group and 4.3 percent of those in the placebo group. The difference between groups was not statistically significant. There were no deaths.

While patients on MPH lost an average of 1.2 Kg during the year, those on placebo remained constant (gained 0.3 Kg). Changes in blood pressure were negligible in both groups. Average heart rate rose by 3 beats per minute in the MPH group, versus a 1 beat per minute decline in the placebo group. There were no significant differences in clinically relevant electrocardiogram abnormalities between the two treatment groups.

Turning to psychological interventions, 90 percent of participants in the GPT group and 94 percent in the CM group experienced at least one adverse event. Differences between the two groups were not statistically significant. Serious adverse events occurred in 3.9% of the GPT participants and 7.7 percent of the CN participants, but again the difference between groups was not statistically significant. There were no clinically relevant changes in weight, blood pressure, or heart rates in these groups throughout the study.

The study team found no modulating effects of either form of psychological treatment on the distribution of adverse events under MPH and placebo treatment.

The authors concluded, "adverse events were found more frequently in patients receiving MPH compared to placebo and were mostly attributable to the centrally stimulating and sympathomimetic action of MPH, including agitation, restlessness, dry mouth, decreased appetite, palpitations, tachycardia [rapid heartbeat], and hyperhidrosis [excessive sweating]. About these adverse events, a causal relationship with MPH seems likely, supported by both the pharmacological effects of MPH as well as previous safety data. ... It is important to note that patients receiving MPH in COMPAS significantly profited from the medication about the reduction of ADHD symptom load, thus the risks of adverse events have to be weighed against the clear benefits. ... Premature termination of MPH due to an adverse event as major reason occurred in less than 10 % of patients and was not statistically significantly different from placebo."

November 21, 2021
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How social disadvantages affect risk of ADHD

How social disadvantages affect risk of ADHD

Danish health care is universal and free. That means there is very complete data available that covers the entire population. The health registers are linked to other national registers that provide access to socioeconomic information. That offers unusual opportunities to research correlations across an entire national population.

Moreover, the health care system requires a high standard for diagnosis of ADHD - evaluation by specialist doctors or psychiatrists rather than a general practitioner. An exception is when parents seek a diagnosis from a private practicing child psychiatrist, in which case diagnostic registration is not mandatory and data is therefore incomplete.

A trio of Danish researchers used the country' national registers to conduct a nationwide population cohort study to explore the cumulative effects of social disadvantages as risk factors for being diagnosed with ADHD.

They looked at all 632,725 children born in Denmark during the 1990s, of which 23,287 (3.7 percent) either had a registered diagnosis in the Patient Registry or else were undergoing ADHD treatment before age 18. Of these, 12,610 children had a registered ADHD diagnosis and entered medical treatment, 4,049 children had a registered diagnosis with no medical treatment, and 6,628 children entered medical treatment with no registered diagnosis. The latter were presumably diagnosed by private practicing psychiatrists. Adjustments were made for gender, immigrant status, birth characteristics (weight, gestational age), single-parenthood, parent ADHD diagnosis, and the number of children in the household.

The study determined that parental educational attainment had the largest effect on the risk of ADHD. Having parents who completed no more than the minimum compulsory education was associated with a 3.5 percentage point higher risk of getting an ADHD diagnosis. Completing no more than upper secondary education was associated with a 1.3 percent higher risk. But there was a sharp bifurcation in the two alternative components of upper secondary education. Children of parents who completed a vocational track faced a 1.7 percent increase in risk, whereas those whose parents completed a college preparatory track faced a negligible 0.17 percent increase.

Parental unemployment also had a significant effect. Youths whose parents were unemployed most of the year faced a 2.1 percent higher risk of ADHD, whereas those whose parents were unemployed less than half the year faced a 1.3 percent higher risk.

Relative income poverty had a comparable impact. Children of parents in the lowest income quintile faced a 2.3 percent higher risk of ADHD than those of parents in the uppermost income quintile. Those in the second-lowest quintile faced a 1.9 percent higher risk than those in the uppermost quintile; those in the middle quintile a 1.3 percent higher risk, and those in the second-highest quintile a 0.8 percent higher risk.

All three cases showed a dose-response relationship, in which higher gradations of social disadvantage were associated with higher levels of risk.

Since these social disadvantages often overlap, the researchers looked at combinations as well and found them to be roughly additive in effect. Parental unemployment plus relative income poverty was associated with a 1.9 percent higher risk of offspring ADHD. Parental unemployment plus completion of no more than compulsory education was associated with a 3.2 percent higher risk. Parental relative income poverty plus completion of no more than compulsory education produced a 4.2 percent higher risk. Finally, Parental relative income poverty plus completion of no more than compulsory education plus unemployment was associated with a 4.9 percent higher risk.

The authors concluded, "This study shows that specific and well-measured parental social disadvantages in terms of unemployment, relative income poverty, and low educational attainment independently affect the risk of ADHD."

November 19, 2021
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Supplements Helping ADHD Symptoms: Anecdotal or Proven?

Meta-analysis claims effectiveness of multi-nutrient supplements in treating ADHD, but reports inconsistent results and has methodological shortcomings

A recently published meta-analysis compared the treatment of ADHD with multi-nutrient supplements versus placebo.

Children received either placebo or Daily Essential Nutrients(Vit A 384 IU, Vit C 40 mg, Vit D 200 IU, Vit E 24 IU, Vit K 8 μg, B1 4 mg, B21.2 mg, B3 6 mg, B6 4.67 mg, B9 50 μg, B12 60 μg, B7 72 μg, B5 2 mg, Ca 88 mg, Fe 0.92 mg, P 56 mg, I 13.6 μg, Mg 40 mg, Zn 3.2 mg, Se 13.6 μg, Cu 0.48 mg, Mn0.64 mg, Cr 41.6 μg, Mo 9.6 μg, P 16 mg. Proprietary blend: Choline bitartrate, Alpha-lipoic acid, Inositol, Acety-l-carnitine (as acetyl-L-carnitine hydrochloride), Grape seed extract, Ginkgo biloba leaf extract, Methionine (asL-methionine hydrochloride), Cysteine (as N-acetyl-L-cysteine), Germanium sesquioxide (as chelate), Boron, Vanadium, Lithium orotate, Nickel. Other ingredients: Cellulose glycine 45 mg, Citric acid 26.814 mg, Magnesium stearate24 mg, Silicon dioxide 20 mg).

Adults received either placebo or EMP+ (Vit A 5760IU, Vit C 600 mg, Vit D 1440 IU, Vit E 360 IU, B1 18 mg, B2 13.5 mg, B3 90 mg,B5 21.6 mg, B6 36 mg, B9 1440 μg, B12 900 μg, Biotin 1080 μg, Pantothenic acid21.6 mg, Ca 1320 mg, Fe 13.74 mg, P 840mg, I 204 μg, Mg 600 mg, Zn 48 mg, Se204 μg, Cu 7.2 mg, Mn 9.6 mg, Cr 624 μg, Mo 144 μg, K 240 mg, Germaniumsesquioxide 20.7 mg, B 2400 μg, V 1194 μg, Ni 29.4 μg, Choline bitartrate 540mg, DL-phenylalanine 360 mg, Citrus bioflavonoids 240 mg, Inositol 180 mg,Glutamine 180 mg, L-methionine 60 mg, Gingko biloba 36 mg, grape seed extract45 mg).

Using the Global Assessment of Functioning (GAF) scale for adults, and the Children's Global Assessment Scale (CGAS) for children, the study team reported moderate improvements in overall functioning from the use of the supplements. GAF and CGAF are used by mental health clinicians and physicians to rate subjectively the social, occupational, and psychological functioning of an individual.

Yet no significant improvements were found for either clinician-rated or observer-rated ADHD Change Scores.

Moreover, the positive finding was compromised by a series of methodological shortcomings:

·        It was just barely a meta-analysis, involving only two studies.
·        The combined number of participants in the two studies was small, 173, consisting of 93 children in one study and 80 adults in the other.
·        Both studies had the same lead author, Julia J. Rucklidge, who was also a member of the meta-analysis team.

With only two studies, there was no way to evaluate publication bias.

October 25, 2023
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Meta-analysis Finds Narrative Language Impairment in Youths with ADHD

Meta-analysis Finds Narrative Language Impairment in Youths with ADHD

Youths with ADHD are known to be more prone to language problems when compared with typically developing peers. To what extent does that affect their ability to share a narrative with others?

A Danish research team conducted a systematic review and meta-analysis of the peer-reviewed medical literature to explore this question. They stressed that this ability is important because "a narrative is a genre of discourse - a form of social communication used to derive meaning from experiences and to construct a shared understanding of events. In other words, it is the fundamental ability of orally producing a coherent story." They focused on the production of narratives rather than comprehension.

Studies had to have a minimum of 10 participants. They had to compare aspects of oral narrative production in children and adolescents with either a formal ADHD diagnosis or a score above a clinical cut-off on a validated ADHD rating scale to a control group of typically developing youths. Youths with confirmed autism spectrum disorder (ASD) or language impairment diagnoses were excluded. There were no constraints on IQ.

The team found sixteen studies with a combined total of 1,015 youths that met these criteria and were suitable for meta-analysis.

They examined seven aspects of oral narrative production:

·        Coherence: A story structure that is logical and easy to follow in cause and sequence. There is a clear beginning, middle, and end. There are goals, attempts, and outcomes. A meta-analysis of nine studies with a combined total of 750 participants found youths with ADHD less coherent than their typically developing peers, with a medium effect size. There was virtually no between-study heterogeneity and no sign of publication bias.
·        Cohesion: This ensures referencing of events and characters in a manner that enables the listener to grasp how characters, events, and ideas in a story are related. Ambiguous or contradictory references get in the way of this. A meta-analysis of eight studies with a combined total of 501 participants found youths with ADHD showed less cohesion than their typically developing peers, with a medium effect size. Again, with virtually no between-study heterogeneity, and no sign of publication bias.
·        Disruptions: These can be sequence errors, misinterpretations, embellishments, or confabulations - fabricating imaginary experiences as compensation for loss of memory. A meta-analysis of six studies with 389 participants found youths with ADHD had more disruptions than their typically developing peers, with a small-to-medium effect size. There was virtually no between-study heterogeneity and no sign of publication bias.
·        Fluency: Best explained in terms of errors that interfere with this quality, such as false starts, repeating words or sentences, and abandoning sentences without completing them. A meta-analysis of four studies with 220 participants found no difference in fluency between youths with ADHD and their typically developing peers.
·        Production: This is a measure of output -overall length of the story, number of sentences, number of words. After adjusting for evidence of publication bias, a meta-analysis of twelve studies with 645 participants found no difference here.
·        Syntactic complexity: This includes the extent of vocabulary and the use of proper grammar. A meta-analysis of six studies with 272 participants found youths with ADHD displayed less syntactic complexity than their typically developing peers, with a small-to-medium effect size. There was virtually no between-study heterogeneity and no sign of publication bi
·        Internal state language: References to perceptions, thoughts, beliefs, and feelings. There were only two studies with 130 participants, so no meta-analysis was performed.

The authors concluded, "the results from the current meta-analysis suggest that children with ADHD have impairments in their narrative language. In particular, children with ADHD produce narratives that are less coherent, less cohesive, less syntactically complex, and include more disruptive errors than typically developing children do."

December 4, 2023
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Safety and Efficacy of Long-term Use of Guanfacine for Adults with ADHD

Safety and efficacy of long-term use of guanfacine for adults with ADHD

Guanfacine extended-release(GXR) is a non-stimulant α2A-adrenergic receptor agonist, approved worldwide for ADHD in children and adolescents.

A Japanese research team set out to explore the long-term administration of once-daily GXR in adults with ADHD over a year of treatment. Their primary objective was to evaluate the safety, and the secondary objective was to evaluate efficacy.

This was an open-label trial. Open-label trials are the opposite of double-blind trials. In a double-blind trial, neither the researchers nor the participants know what treatment they participants are receiving. In an open-label trial, on the other hand, both the researchers and participants know what treatment the participant is receiving, which can introduce significant bias. These studies are therefore at the lowest rung in the evidentiary base.

It is worth noting, however, that the risk of bias would be primarily for efficacy, and the primary aim of the trial was to evaluate safety.

The trial was funded by the manufacturer, but preregistered, a way of assuring that results would be released regardless of the outcome.

The study population consisted of 191 ADHD patients 18 and older at 71 locations in Japan. There was no control population. The 50-week flexible titrated dosing treatment period was followed by a 2-week period over which doses were gradually reduced, and then a one-week follow-up period. That means the trial covered an entire year. Of the enrolled patients, 67 dropped out, mostly due to adverse events, leaving 124 patients after the trial.

A total of 830 treatment-emergent adverse events (TEAEs) were reported by 180 patients. One in five patients (34)discontinued treatment due to adverse events. The most commonly reported adverse events were somnolence, thirst, nasopharyngitis, decreased blood pressure, postural dizziness, bradycardia (abnormally slow heartbeat), malaise, constipation, and dizziness. Except for nasopharyngitis, all were considered related to the medication. There were two serious adverse events, one unrelated to the medication, the other a supraventricular tachycardia (abnormally fast heart rhythm arising from improper electrical activity in the upper part of the heart) in a patient simultaneously medicated for a preexisting condition. The patient recovered after treatment and discontinuation of GXR.

The main TEAEs resulting in Discontinuation were somnolence (nine patients), blood pressure reduction (eight patients), malaise (six patients), and bradycardia (four patients, with only one case considered severe), and postural dizziness (three patients) or dizziness(three patients).

Significant reductions in ADHD scores and improvements in executive functioning were measured across the study population following a year's GXR treatment. Again, this was not the primary aim of the trial, and double-blinded randomized controlled trials are the gold standard.

The authors concluded that "there were no new or unexpected safety concerns" and "patients who received dose-optimized GXR had improvements in multiple aspects of ADHD, including symptoms, QoL [Quality of Life], and executive functioning," but acknowledged, "There was a potential for observer bias because of the open-label nature of the study, and the findings may not be representative of real-world settings because patients with psychiatric or cardiovascular comorbidities, which are common in patients with ADHD, were excluded. In addition, there was a potential bias favoring safety and efficacy for continuing patients because those who discontinued owing to adverse events or lack of efficacy were not eligible for inclusion."

October 23, 2023
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A nationwide population study examines sleep problems in youth with ADHD

A nationwide population study examines sleep problems in youth with ADHD

Denmark has a universal health insurance system that requires tracking all health care data in a system of national registries. That makes it possible to explore what's going on in an entire national population, rather than have to rely on sampling a small part of it, and hoping the sampling is reasonably representative.

A team of Danish researchers used the Civil Registration System to identify all single births through 1993 through 2014 and linked those records to corresponding records in the Psychiatric Central Research Register and National Patient Register for the years 2011through 2016. There were 1,397,850 youths in that cohort, of whom 12,844 were diagnosed with ADHD during the study period.

At five years of follow-up after diagnosis, almost three in ten youths with ADHD (29 percent) had registered evidence of sleep problems (including the use of melatonin, which is by prescription only in Denmark). For those with concomitant conduct disorder, almost half (45 percent) had registered evidence of sleep problems.

In the general population, on the other hand, the cumulative risk of sleep problems at five years of follow-up varied from one in a hundred for children followed from age 5 or age 10 to one in forty for those followed from age 15.

After adjusting for the confounding effects of three other neurodevelopmental disorders - autism spectrum disorder, oppositional defiant disorder/conduct disorder, and epilepsy­- youths with ADHD were still roughly 23 times more likely to have sleeping problems than were normally developing youths.

The authors cautioned, however, that the low rate of sleep problems in the general population "may indicate that sleeping problems without coexisting neurodevelopmental disorders are generally diagnosed or treated in primary health care (and hence not included in our study)."

A further limitation, they added, is that "we can not exclude the possibility of residual confounding. Thus, it remains unclear whether neurodevelopmental disorder contributes to the sleep problem or whether certain unmeasured characteristics of children with neurodevelopmental disorders may explain the apparent association with sleep problems."

September 27, 2023
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Meta-analysis Finds Association Between Postnatal Secondhand Smoke and ADHD

Meta-analysis finds association between postnatal secondhand smoke and ADHD

Secondhand smoke (SHS) is tobacco smoke inhaled by nonsmokers sharing enclosed spaces with smokers. It contains well over two hundred toxic chemicals, including some toxic metals known to cause serious harm to humans. It is among the most common indoor air pollutants worldwide, with roughly two in five children exposed.

Until now, studies have focused primarily on maternal smoking before childbirth. A Chinese research team set out to explore what, if any, association there might be between childhood exposure to SHS and ADHD. They conducted a comprehensive search of the peer-reviewed literature and identified nine studies with a combined total of over a hundred thousand participants that looked for such effects. The studies were carried out in the United States, Germany, Spain, and the Republic of Korea.

Merging these studies into a meta-analysis, the team found that children exposed to secondhand smoke were 60 percent more likely to develop ADHD. The same overall pattern held true on all three continents.

A further meta-analysis of four of the studies with over 12,000 participants found children exposed to secondhand smoke were 33% more likely to exhibit conduct problems.

The authors concluded, "The results of our meta-analysis suggest that postnatal exposure to SHS may be associated with ADHD in children. Exposure to SHS can also lead to a variety of adverse behavioral outcomes in children. Therefore, parents should stop smoking to create a good growing environment for their children. Further prospective studies should fully adjust for potential confounding factors to determine whether there is a causal relationship between SHS and ADHD."

December 4, 2023
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Study Finds Montelukast Treatment for Asthma is Not a Risk Factor for ADHD

Nationwide cohort study indicates montelukast treatment for asthma not a risk factor for ADHD

Montelukast is a leukotriene receptor antagonist that binds to the cysteinyl leukotriene type 1 receptor. It thereby blocks the action of leukotriene, an inflammatory mediator produced by white blood cells. By binding with the receptors, montelukast decreases the inflammation associated with asthma, relaxing smooth muscles and dilating air passages. Though used as an alternative to inhaled corticosteroids for mild persistent asthma, it is not suitable for acute attacks.

Previous smaller studies have produced inconsistent results on whether montelukast treatment is a risk factor for ADHD. That led a Taiwanese research team to conduct a nationwide cohort study. They used the Nationwide Health Insurance Research Database (NHIRD), consisting of a million randomly selected participants drawn from the Taiwan's universal single-payer health insurance system.

The team identified a total of 53,645 children 12 years old and under-diagnosed with asthma. Of these, 17,773 were treated with montelukast, and 35,912 were not. The two groups were then matched on a 1:1 ratio for age, sex, geographic region of residence, comorbidities including allergic rhinitis and atopic dermatitis, admission or emergency department visits due to an asthma attack, and index date. That yielded a montelukast group of 12,806 and an identically sized control group.

Both in the crude and adjusted results, children treated with montelukast were found to be no more likely to develop ADHD than those not treated with montelukast (p = .5). Longer treatment with montelukast (over 90 days) had no effect, with an adjusted hazard ratio of exactly 1.00 (p = .95).

The authors concluded, "Our current findings indicate that exposure to montelukast among pediatric asthma patients poses no increased risk of attention-deficit/hyperactivity disorder. Montelukast therapy, which may be necessary for pediatric patients with asthma, is a safe therapy for such patients."

October 31, 2023
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Why are children born in August more likely to be diagnosed with ADHD?

Why are children born in August more likely to be diagnosed with ADHD?

Taiwan's single-payer National Health Insurance system encompasses its entire population, and it's National Health Insurance Research Database tracks all medical claims in the system. That makes it easy to conduct nationwide population studies.

Two Taiwanese research teams availed themselves of that database to explore in-depth a surprising relationship between the birth month of children and rates of ADHD diagnosis.

In principle, the two should be unrelated. The likelihood of diagnosis should be the same regardless of the month a child is born. But the data are clear that this is not so. Children born late in summer are the most likely to be diagnosed with ADHD, and those in autumn are the least likely.

Using a nationwide database of over 29 million persons, one of the teams (Hsu et al.) found that children born in April were 6% more likely to be diagnosed with ADHD than the year-round mean, those in May 12% more likely, those in June 20% more likely, and those in July and August well over 25% more likely.

Conversely, children born in September were 19% less likely to be diagnosed with ADHD than the year-round mean, followed by a gradual increase in likelihood with each succeeding month until the following September.

The second team (Chen et al.) analyzed some 9.5 million children and adolescents in the same reserch database, and found that those born in August were 67% more likely to be diagnosed with ADHD than those born in September, after adjusting for age, sex, residence, and income. August births were also almost twice as likely (80% more likely) as September births to be on long-term treatment with ADHD medications.

The first team also performed a meta-analysis of eleven studies with a combined total of over 580,000 participants in North America (the U.S. and Canada), Europe (U.K., Germany, Norway, Sweden, Denmark), Asia (China, Taiwan, South Korea), and Oceania (Australia). Children born in the summer (June through August) were 13% more likely to be diagnosed with ADHD than the year-round mean, whereas those born in autumn were 13% less likely to be diagnosed with ADHD. This confirms that this pattern is not confined to Taiwan. It is worldwide.

Note carefully that the sharp discontinuity between August and September corresponds with the break-of point that decides which children get assigned to which school class. Anyone who turns a certain age by the start of the school year in September is included in the class associated with that age, whereas those turning the same age later are held back in the following class. That means that in any given class, those born in September are the oldest children and those born in August the youngest.

As signaled earlier, the likelihood of an ADHD diagnosis should be independent of something as obviously arbitrary as a birth month. That suggests there may be an unconscious bias trending against younger students when it comes to diagnosis.

Chen et al. concluded, "The effect of relative age on diagnoses and prescriptions was determined to last from childhood to adolescence but attenuated with age. Relative age is an indicator of brain maturity in cognition, behavior, and emotion and may thus play a critical role in the likelihood of being diagnosed as having childhood mental disorders and subsequently being prescribed psychotropic medication. Therefore, clinicians should consider the relative age effect in the childhood mental health care context."

September 14, 2023
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A Norwegian nationwide cohort study finds link between prescribed drugs widely used as sleeping aids and subsequent ADHD

A Norwegian nationwide cohort study finds link between prescribed drugs widely used as sleeping aids and subsequent ADHD

There have been indications that infants who have difficulty sleeping are more likely to later develop ADHD in childhood. Would this hold up in a large nationwide cohort study?

Noting that "Norway has several national health registries with compulsory and automatically collected information," and "registries can be linked on an individual level, making it possible to conduct large cohort studies," a Norwegian team of researchers studied the association between sleep-inducing medications prescribed to infants under three years old and diagnoses of ADHD between the ages of five and eleven.

Norway has a national health insurance system that covers all residents, and pays in full for youths under 16 years old. Norwegian pharmacies must register all dispensed prescriptions into a national register as a prerequisite for reimbursement.

The study included all children born in Norway from 2004 through 2010, minus those who died or emigrated, leaving a total of 410,555 children.

In addition to traditional hypnotic and sedative drugs and melatonin, the study looked at antihistamines, which though intended for respiratory use, are frequently used for gentle sedation.

The two most frequently prescribed drugs were found to be dexchlorpheniramine (girls 7%, boys 8%) and trimeprazine(girls 3%, boys 4%), both of which are antihistamines.

After adjusting for parental education as an indicator of family socioeconomic status, and parental ADHD as indicated by prescription of ADHD medications, girls who had been prescribed sleeping medications on at least two occasions were twice as likely to subsequently develop ADHD, and boys about 60 percent more likely. For, dexchlorpheniramine equivalent associations were not statistically significant for either boys or girls. But girls prescribed trimeprazine on at least two occasions were almost three times as likely to subsequently develop ADHD, and boys were well over twice as likely.

A limitation of the study was that there was no direct data for sleep diagnosis. The authors noted, "The Norwegian prescription database does not contain diagnosis unless medications are reimbursed and hypnotics are not reimbursed for insomnia or sleep disturbances in general. Sleep diagnoses were also not available from the Norwegian Patient Registry, as there seems to be a clinical tradition for not using the ICD- 10G47 Sleep Disorders diagnosis for children."

The authors concluded, "It has previously been shown that infant regulation problems, including sleep problems, are associated with ADHD diagnosis. We replicate this finding in a large cohort, where continuous data collection ensures no recall bias and no loss to follow-up. We find that the use of hypnotic drugs before 3 years of age, signifying substantial sleeping problems, increases the risk of a later ADHD diagnosis. This was especially true for the antihistaminic drug, trimeprazine."

September 25, 2023
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