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.

Related posts

No items found.

Cohort Study Finds ADHD Link to Higher Mortality is Mediated by Comorbid Anxiety and Depression

The Background:

Previous research has suggested that people with ADHD have higher rates of death than those without the condition. Until now, many of those studies lacked the detail needed to untangle why this might be the case. A recent meta-analysis of eight separate studies reported that ADHD roughly doubled the risk of death, and it hinted that factors like socioeconomic status and other mental illnesses might help explain the link.  

The Study: 

To explore this in more detail, researchers used the US National Health Interview Survey, a nationally representative prospective cohort of just over 52,000 adults. Survey records were linked with the National Death Index, and participants were followed from the date of interview until death or December 31, 2019, whichever came first. The main outcome was death from any cause. With a median follow-up of just under eight years, there were 6,024 deaths recorded. 

When the team adjusted their analysis for age, sex, ethnicity, and the year of the survey, having ADHD was associated with a 58% higher risk of death. Controlling further for family income and educational level reduced that increased risk slightly, to 50%. 

Controlling for health conditions (like high blood pressure, diabetes, stroke, heart disease, and cancer) and lifestyle factors (smoking, alcohol use, physical activity, and body weight) also reduced the association to about 46%. 

By contrast, when the researchers adjusted for two psychiatric conditions (anxiety and depression) commonly found alongside ADHD, the link between ADHD and higher mortality disappeared statistically. In other words, once anxiety and depression were taken into account, ADHD itself was no longer associated with a clearly measurable increase in the risk of death. 

What Does This Mean?

The authors conclude that the apparent effect of ADHD on mortality seems to operate largely through accompanying mental illness, and to a lesser extent through lifestyle and physical health problems. They suggest that treating and managing these co-occurring issues (through medications, therapy, and behavioral interventions) might help reduce the risk of premature death in people with ADHD, although they note that further evidence is needed. 

‍

October 14, 2026

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. 

‍

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.

‍

October 1, 2026