November 21, 2021

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."

Bernhard Kis, Caroline Lücke, Mona Abdel-Hamid, Philipp Heßmann, Erika Graf, Mathias Berger, Swantje Matthies, Patricia Borel, Esther Sobanski, Barbara Alm, Michael Rösler, Wolfgang Retz, Christian Jacob, Michael Colla, Michael Huss, Thomas Jans, Ludger Tebartz van Elst, Helge H. O. Müller, Alexandra Philipsen, "Safety Profile of Methylphenidate Under Long-Term Treatment in Adult ADHD Patients - Results of the COMPAS Study," Pharmacopsychiatry (2020), https://doi.org/10.1055/a-1207-9851.

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Taiwan Nationwide Population Study Finds Link Between ADHD and Early Puberty, Also Protective Effect of Methylphenidate

Precocious puberty (PP) is defined as the onset of secondary sex characteristics before age 8 in girls or age 9 in boys.  

Because it accelerates skeletal maturation by prematurely shutting down the cartilage growth plate at the tip of long bones, it tends to lead to shorter height in adulthood. It is also known to place an additional psychological burden on children, especially girls. Girls are four to 38 times more likely to develop PP than boys. 

Taiwan has a single-payer national health insurance system, called National Health Insurance, that encompasses 99.6% of the island’s population. The Ministry of Health and Welfare uses it to maintain the National Health Insurance Research Database (NHIRD), enabling researchers to conduct nationwide population studies. 

Using this database, a Taiwanese study team investigated the relationship between ADHD and precocious puberty among children and adolescents (under 18). And because methylphenidate (MPH) is the only psychostimulant approved for the treatment of ADHD in Taiwan, the team also explored the effect of MPH on this relationship. 

Most diagnoses of ADHD in the NHIRD are made by board-certified psychiatrists, enhancing diagnostic validity. 

Of the more than 3.3 million persons born in Taiwan between 1997 and 2001, 186,681 were diagnosed with ADHD. Of these, 122,302 were prescribed MPH. 

After adjusting for sex, low-income households, and neuropsychiatric comorbidities, children diagnosed with ADHD were twice as likely to be diagnosed with PP. This held equally true for boys and girls. 

However, children diagnosed with ADHD and prescribed MPH were more than a third less likely to subsequently be diagnosed with PP than those diagnosed with ADHD but not prescribed MPH.  

For girls with ADHD, who without an MPH prescription were nine times more likely than boys with ADHD to be diagnosed with PP, an MPH prescription reduced that ratio to five times more likely than boys with ADHD and prescribed MPH. 

That suggests a strong protective effect of MPH.  

The team concluded, “Our study found that children with ADHD were at a greater risk of PP, and girls with ADHD were a particularly vulnerable group. … MPH appeared to be protective against PP in patients with ADHD, especially in girls. However, these preliminary results need further validation.” 

Taiwan Nationwide Population Study Finds No Effect of Maternal and Childhood Infection on Subsequent Offspring ADHD in Sibling Comparisons

Population Study Finds No Effect of Maternal and Childhood Infection on Subsequent Offspring ADHD

Maternal infections and inflammatory responses during pregnancy have been proposed as risk factors for neurodevelopmental disorders such as ADHD. 

Taiwan has a single-payer health insurance system that covers virtually the entirety of its population. Its Ministry of Health and Welfare maintains the National Health Insurance Research Database (NHIRD), with detailed information on outpatient services, hospitalizations, and medical treatment for nearly 99% of all residents. 

A Taiwanese study team used NHIRD to examine to examine the relationship between maternal hospitalization for infection, and early childhood infection, and subsequent ADHD in offspring. The study cohort originated with all 3,260,879 individuals born between 2001 and 2018. 

The team excluded births from foreign mothers, still births, births with congenital defects, low birth weights, abnormally late births, twins, triplets, and other multiple births, culminating in a final population cohort of 2,885,662 live-born single infants across 1,893,171 families, and 1,864,660 individuals with full siblings from 872,169 families comprising the full sibling cohort. 

Study participants were followed until diagnosis of a neurodevelopmental disorder, their death, or the end of 2021. 

After adjusting for sex, birth year, paternal and maternal ages, birthweight, birth season, parity, delivery method, 1 minute APGAR score (evaluating baby’s appearance, pulse, grimace, activity and respiration at birth), gestational age, pregnancy and delivery complications, parental history of neurodevelopmental disorders, maternal asthma and diabetes, urbanization level of the residential area, and family’s insurance amount, offspring of mothers hospitalized for infections had 14% greater odds of being subsequently diagnosed with ADHD. 

However, in the full sibling cohort of over 1.8 million, this association vanished. That held true for each of the three trimesters of pregnancy. It also held true for bacterial infections. Surprisingly, offspring of mothers hospitalized for viral infections were 24% less likely to be diagnosed with ADHD than their siblings not exposed to maternal viral infection. Because of that, they also had a 6% lower risk overall. 

After the same adjustments, early childhood infection was associated with 16% greater odds of being diagnosed with ADHD. 

Nevertheless, in the full sibling cohort of over 1.8 million, this association again vanished. That held true overall, as well as separately for childhood infections in months 1-6 and months 7-12. The association vanished altogether both for bacterial infections as well as for viral infections. 

The authors concluded, “the results of this nationwide birth cohort study with population and sibling analyses suggest that the association between maternal infection during pregnancy and offspring neurodevelopmental risk is largely due to familial confounding factors.” 

March 25, 2025

Australian Nationwide Survey Finds More Than Tenfold Greater Odds of Suicidality or Self-harm Among Children with ADHD

Most previous studies of suicide and self-harm risk among persons with ADHD have focused on adolescents and adults. They’ve also tended to be cross-sectional, analyzing data from a population at a specific point in time. 

An Australian study team took a different approach, conducting a before-and-after study through the birth cohort of the Longitudinal Study of Australian Children (LSAC), comprising 5,107 children who have been followed up every two years since birth. 

The diagnosis of ADHD was based on parents reporting that their child had received a diagnosis of ADHD at or before age ten.  

Suicide and self-harm were defined as children’s self-report at age 14 of any thought or attempt of suicide and self-harm respectively over the past year. 

The team adjusted for the following confounders: socioeconomic status, birth weight, ADHD medication history, maternal education level, maternal age at birth, experience in bullying victimization at age 12, and depression score based on Short Mood and Feelings Questionnaire (SMFQ). 

Of the 5,107 participants, 3,696 had all the valid data required for analysis and were included in the final cohort. Of these, 3.6% were diagnosed with ADHD by age 10. 

With diagnosis of ADHD at age 10 and all other factors held constant: 

  • The odds of suicidal thought, plan, or attempt at age 14 increased elevenfold. This was twice as pronounced among boys as among girls. 
  • The odds of self-harm at age 14 increased 25-fold. This was more than three times as pronounced among boys as among girls. 

Both depression and exposure to bullying were statistically significant mediators for the relationship. Nevertheless, depression and exposure to bullying each accounted for well under 10% of the overall effect. 

Neither socioeconomic status nor maternal factors had any significant mediating effect on outcomes. 

Conclusion:

The authors concluded, “This study provides compelling evidence that children diagnosed with ADHD at the age of 10 years face significantly elevated risks of experiencing suicidal thoughts, planning, or attempts, as well as self-harm, by the age of 14 years, which underscores the critical importance of recognizing and addressing these heightened risks in children with ADHD.” 

While factors like depression and bullying contribute, ADHD itself remains a key risk factor. Early intervention and strong mental health support are crucial to protecting these children’s well-being.

March 21, 2025