July 8, 2021

High Dropout Rate in Six-Year Cohort Study of Medication Treatment for ADHD

Few studies have examined the safety and tolerability of ADHD medications (stimulants and atomoxetine) extending beyond six months, and none beyond a few years. A pair of Swedish neuroscientists at Uppsala University Hospital set out to explore longer-term outcomes. They conducted a six-year prospective study of 112 adults diagnosed with ADHD who were being treated with ADHD medications (primarily MPH, but also dexamphetamine and atomoxetine).


They found that at the end of that period, roughly half were still on medication, and half had discontinued treatment. There were no significant differences between the two groups in age, sex, ADHD severity, or comorbidity. The average ADHD score for the entire cohort declined to vary significantly, from a mean of 37 to a mean of 26, with less than one in a thousand odds of that being due to chance. There was also no sign of drug tolerance or a need to increase the dosage over time.
All 55 adults who discontinued treatment had taken MPH for at least part of the time. Eleven had also been treated with dexamphetamine(DEX) and 15 with atomoxetine (ATX). The average time on treatment was just under two years. Almost a third quit MPH because they perceived no beneficial effect. Since they were on average taking higher doses at discontinuation than initiation, that is unlikely to have been due to suboptimal dosage. Almost another third was discontinued for various adverse mental effects, including hyperactivity, elation, depressive moods, aggression, insomnia, fatigue, and lethargy. Another one in eleven quit when they lost contact with the prescribing physician. In the case of ATX, almost half quit because of what they perceived as adverse mental effects.


Among the 57 adults who remained on medication, four out of five reported a strong beneficial effect. Only two reported minimal or no effect. Compared with the group that discontinued, the group that remained on medication was far more likely to agree with the statements, "My quality of life has improved," and "My level of functioning has improved." Yet, as the authors caution, it is possible "that the subjects' subjective ratings contained a placebo-related mechanism in those who are compliant with the medication and pursue treatment over time." The authors reported that there were no significant differences in ADHD scores or ADHD severity between the group that quit and the group that remained on medication, even though, on average, the group that quit had been off medication for four years at follow-up.


We cannot explain why the patients who quit treatment showed similar levels of ADHD symptoms to those who continued treatment.  It is possible that some patients remit symptoms over time and do not require sustained treatment.  But we must keep in mind that there was a wide range of outcomes in both groups. Future work needs to find predictors of those who will do well after treatment withdrawal and those who do not.


Any decision on whether to maintain a course of medication should always weigh expected gains against adverse side effects. Short of hard evidence of continuing efficacy beyond two years, adverse events gain in relative importance. With that in mind, it is worth noting that this study reports that among those who remained on MPH, many reported side effects. More than a quarter complained of decreased appetite, one in four of dry mouth, one in five of anxiousness and increased heart rate, one in six of decreased sexual desire, one in nine of depressed mood, and one in eleven of insomnia.


This study breaks important ground in looking at the long-term effects of medication. It reaffirms findings elsewhere of the efficacy of ADHD medications. But contrary to the authors' conclusion, the data they present suggests the possibility that permanently medicating ADHD patients may not be more efficacious than discontinuation beyond a certain point, especially when balanced against adverse side effects.
But this is just one study with a relatively small sample size. This suggests a need for additional studies with larger sample sizes to pursue these questions with greater statistical reliability.

Dan Edvinsson and Lisa Ekselius, "Long-Term Tolerability and safety of Pharmacological Treatment of Adult Attention-Deficit/hyperactivity disorder," Journal of clinical psychopharmacology, vol. 38, no. 4(2018).

Related posts

No items found.

New Global Estimate of Adult ADHD Prevalence: A Comprehensive Review

Adult ADHD has long been a subject of debate in the field of mental health, with previous estimates of its prevalence varying widely. To achieve a more precise understanding, an international team of researchers conducted a new umbrella review and meta-analysis, offering an updated estimate of adult ADHD rates worldwide.

A Comprehensive Approach: Reviewing 57 Studies

This large-scale analysis combined five systematic reviews and meta-analyses, incorporating data from 57 unique primary studies. Altogether, the research synthesized findings from a pooled total of over 21 million participants. This comprehensive approach provided a more accurate estimate of the global prevalence of ADHD in adults.

Key Findings: 3.1% Global Prevalence

The study concluded that the worldwide prevalence of adult ADHD is 3.1%, with a 95% confidence interval ranging from 2.6% to 3.6%. This estimate falls within the range of earlier reports but provides a more targeted understanding of the rate at which ADHD affects adults globally.

Putting the Numbers in Context

The researchers described this prevalence rate as “relatively high.” They noted that it is only slightly lower than the estimated prevalence of major mental health conditions like schizophrenia (4%) and major depressive disorder (5%)—disorders that have historically received significant attention and resources worldwide.

Moreover, the prevalence of adult ADHD is higher than that of several other well-known mental health conditions, including bipolar disorder (1%), as well as anxiety disorders such as PTSD (Post-Traumatic Stress Disorder), OCD (Obsessive-Compulsive Disorder), GAD (Generalized Anxiety Disorder), and panic disorders.

Implications for Awareness and Treatment

This updated estimate emphasizes that ADHD is a significant global mental health concern in adults, comparable to or exceeding the prevalence of other disorders that are often more widely recognized. These findings underscore the need for greater awareness, research, and treatment options for adult ADHD, which is still frequently misunderstood or overlooked in the broader discourse of mental health.

Conclusion

By providing a clearer picture of how prevalent ADHD is in adult populations around the world, this study contributes valuable data that could shape future research, policy, and clinical approaches.

November 8, 2024

Updated Analysis of ADHD Prevalence in the United States: 2018-2021

Attention-Deficit/Hyperactivity Disorder (ADHD) remains a prevalent condition among children and adolescents in the United States. A recent analysis based on the National Health Interview Survey (NHIS), conducted by the National Center for Health Statistics at the CDC, provides an updated look at ADHD prevalence from 2018 to 2021. Here’s a closer look at what the data reveals.

How the Survey Works

The NHIS is an annual survey primarily conducted through face-to-face interviews in respondents’ homes. Telephone interviews are used as a substitute in cases where travel is impractical. For each family interviewed, one child aged 3-17 is randomly selected for the survey through a computer program. Over the four years studied (2018-2021), a total of 26,422 households with children or adolescents participated.

Overall ADHD Prevalence and Age-Related Trends

The analysis found that 9.5% of children and adolescents in the United States had been diagnosed with ADHD, based on reports from family members. However, the prevalence varied significantly with age:

  • Ages 3-5: 1.5%
  • Ages 6-11: 9.6%
  • Ages 12-17: 13.4%

The increase in ADHD diagnosis with age underscores the importance of monitoring children’s developmental needs as they progress through school and adolescence.

Gender Differences: Higher Rates Among Males

The survey revealed a notable difference in ADHD prevalence between genders, with 12.4% of males diagnosed compared to 6.6% of females—nearly a two-to-one gap. This aligns with previous research indicating that ADHD is more frequently diagnosed in boys than girls, though awareness of how ADHD presents differently across genders is growing.

Family Income and ADHD Rates

Family income played a significant role in ADHD prevalence, particularly among lower-income groups:

  • Below the poverty line: 12.7%
  • Above the poverty line but less than twice that level: 10.3%
  • Above twice the poverty level: 8.5%

This pattern suggests that socioeconomic factors might influence the diagnosis and management of ADHD, with lower-income families possibly experiencing greater barriers to early diagnosis or consistent treatment.

Regional Differences Across the U.S.

Geographic location also impacted ADHD rates. Prevalence was highest in the South (11.3%), followed by the Midwest (10%), the Northeast (9.1%), and significantly lower in the West (6.9%). These variations could reflect regional differences in healthcare access, diagnostic practices, or cultural attitudes towards ADHD.

Stability Over Time

Despite these variations in demographics, the overall prevalence of ADHD remained relatively stable across the study period from 2018 to 2021, showing no significant changes by year.

What This Means for Families and Healthcare Providers

The findings from this updated analysis provide a clearer picture of ADHD’s prevalence across different demographic groups in the United States. They highlight the need for tailored approaches to diagnosis and care, taking into account factors like age, gender, income, and geographic location. With ADHD being a common condition affecting nearly 1 in 10 children, ongoing research and support for families are crucial to ensure that those with ADHD receive the care and resources they need.

Conclusion: 

This study reinforces the importance of awareness and early intervention, especially for families in underserved regions or those facing economic challenges. As clinicians and educators continue to support children with ADHD, understanding these demographic trends can help in creating more equitable access to diagnosis and treatment.

October 29, 2024

Meta-Analysis Shows No Significant Impact of Caffeine on ADHD Symptoms

Stimulant medications like methylphenidate and amphetamines are well-established treatments for reducing ADHD symptoms, making a notable difference in focus and behavior. Given that caffeine is also a stimulant, researchers have wondered whether it might offer similar benefits for managing ADHD symptoms. A recent meta-analysis conducted by a Brazilian research team sought to explore this question.

The Search for Evidence: A Limited Pool of Studies

The researchers faced an immediate challenge: there is surprisingly little research directly investigating caffeine's effects on ADHD symptoms. After a thorough review of peer-reviewed literature, they identified only four randomized controlled trials (RCTs) suitable for their analysis, encompassing a combined total of just 152 participants.

The limited number of studies—and participants—meant that the meta-analysis was not as robust as the research team might have hoped. However, they proceeded to examine the available data to determine whether caffeine showed any measurable benefit over a placebo.

Findings: Minimal Impact, No Statistical Significance

The results of the meta-analysis showed a slight decrease in ADHD symptoms among those who consumed caffeine compared to those given a placebo. However, this reduction was not statistically significant. The small sample size likely played a role in this outcome, making the study underpowered. Even if future studies with larger groups of participants were to show statistical significance, the observed effect size would likely remain too small to be clinically meaningful.

Interestingly, the four trials included in the meta-analysis showed very little variation in their findings. Each study slightly favored caffeine over placebo, but none came close to achieving statistical significance.

Conclusion: Caffeine Is Not a Substitute for ADHD Medications

Ultimately, the researchers concluded that “overall, the totality of the evidence suggests no significant benefit of caffeine over placebo in the treatment of children with ADHD.” The findings indicate that while caffeine might produce a slight reduction in symptoms, it is not an effective alternative to established ADHD treatments like methylphenidate or amphetamines.

This study highlights the importance of relying on proven medications for ADHD management rather than seeking alternatives that lack substantial evidence. While caffeine might offer a slight stimulant effect, it falls short of delivering the therapeutic benefits needed for those with ADHD to manage their symptoms effectively. For clinicians, parents, and individuals with ADHD, these results underscore the value of evidence-based treatments in improving quality of life and daily functioning.

October 28, 2024