December 18, 2024
Attention deficit hyperactivity disorder (ADHD) is a neurodevelopmental condition that persists into adulthood for most individuals, affecting 60% to 90% of those diagnosed as children. However, understanding ADHD in older adults, particularly those over 50, remains limited. With the U.S. population aged 65+ projected to nearly double by 2050, this oversight has critical implications for healthcare.
A recent analysis of 20 studies (sample size: over 20 million) highlights ADHD prevalence in the elderly as 2.18% when community scales are used but only 0.23% when clinical diagnoses are reviewed in medical records. This discrepancy points to underdiagnosis and the need for clinician education. Furthermore, treatment rates are alarmingly low, with just 0.09% of elderly individuals receiving ADHD medications.
Current diagnostic criteria, still rooted in studies of youth, inadequately address age-specific symptoms. Barkley and Murphy’s screening tool is one step forward, but its moderate reliability signals the need for refinement. Diagnostic challenges grow more complex as clinicians must differentiate ADHD from cognitive changes due to aging, medical conditions, or psychiatric disorders like depression or dementia. The concurrent presence of conditions further complicates assessments and treatments.
Treatment hesitancy also hampers care. Concerns about cardiovascular risks, interactions with other medications, and lack of familiarity with ADHD medication dosing in older adults fuel clinician caution. While psychostimulants are generally safe when carefully managed, misconceptions about abuse and addiction persist, creating unnecessary barriers.
Addressing ADHD in older adults requires dedicated clinician training to overcome biases, refine diagnostic tools, and balance medical risks with the significant quality-of-life benefits ADHD treatment offers. With more research, improved clinical protocols, and better education, older adults with ADHD can receive accurate diagnoses and effective treatment. This will help them maintain cognitive function and independence, significantly enhancing their lives.
Goodman, D. W., Cortese, S., & Faraone, S. V. (2024). Why is ADHD so difficult to diagnose in older adults? Expert Review of Neurotherapeutics, 24(10), 941–944. https://doi.org/10.1080/14737175.2024.2385932
The current Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) requires evidence of symptom onset before age 12 to make a diagnosis of ADHD in adults.
A recently published clinical review questions the appropriateness of this criterion in older adults 50 years old and above. It sets forth several reasons:
On the other hand, the reason for the early onset criterion is to avoid any confusion with early neurodegenerative diseases such as Alzheimer's or Lewy body dementia, which have overlapping symptoms.
The authors suggest a possible fix:
It is unethical, the authors suggest, to deny care to older, presently undiagnosed adults, given the demonstrated poor outcomes associated with untreated ADHD.
The CDC recently reported that ADHD medication use in women ages 15 to 44 increased from 0.9 percent to 4 percent from 2003 to 2015. The most commonly used medications were formulations of amphetamine or methylphenidate.
This increase in treatment for ADHD suggests that educational programs such as adhdinadults.com have been effective in teaching clinicians how to identify and treat the disorder. The 4 percent rate reported by the CDC is encouraging because it is close to what Ron Kessler and colleagues reported as the prevalence of adult ADHD in the population. CDC correctly points out that little is known about the effects of ADHD medications on pregnancies. Thus, caution is warranted.
Oei et al.'s review of amphetamines concluded: "There is little evidence of amphetamine-induced neurotoxicity and long-term neurodevelopmental impact, as data is scarce and difficult to extricate from the influence of other factors associated with children living in households where one or more parent uses drugs in terms of poverty and neglect. ... We suggest that exposed children may be at risk of ongoing developmental and behavioral impediment, and recommend that efforts be made to improve early detection of perinatal exposure and to increase the provision of early intervention services for affected children and their families"
Bolea-Alamanac et al.'s review of methylphenidate effects concluded: "There is a paucity of data regarding the use of methylphenidate in pregnancy and further studies are required. Although the default medical position is to interrupt any non-essential pharmacological treatment during pregnancy and lactation, in ADHD this may present a significant risk. Doctors need to evaluate each case carefully before interrupting treatment." These words of caution should be heeded by clinicians caring for women of reproductive age.
Older adults are at greater risk for cardiovascular disease. Psychostimulants may contribute to that risk through side effects, such as elevation of systolic blood pressure, diastolic blood pressure, and heart rate.
On the other hand, smoking, substance abuse, obesity, and chronic sleep loss - all of which are associated with ADHD - are known to increase cardiovascular risk, and stimulant medications are an effective treatment for ADHD.
So how does this all shake out? A Dutch team of researchers sets out to explore this. Using electronic health records, they compared all 139 patients 55 years and older at PsyQ outpatient clinic, Program Adult ADHD, in The Hague. Because a principal aim of the study was to evaluate the effect of medication on cardiovascular functioning after first medication use, the 26 patients who had previously been prescribed ADHD medication were excluded from the study, leaving a sample size of 113.
The ages of participants ranged from 55 from 79, with a mean of 61. Slightly over half were women. At the outset, 13 percent had elevated systolic and/or diastolic blood pressure, 2 percent had an irregular heart rate, 15 percent had an abnormal electrocardiogram, and 29 percent had some combination of these (a "cardiovascular risk profile"), and 21 percent used antihypertensive medication.
Three out of four participants had at least e comorbid disorder. The most common are sleep disorders, affecting a quarter of participants, and unipolar mood disorders (depressive or more rarely manic episodes, but not both), also affecting a quarter of participants.
Twenty-four patients did not initiate pharmacological treatment. Of the 89 who received ADHD medication, 58 (65%) reported positive effects, and five experienced no effect. Thirty-eight (43%) discontinued ADHD medication while at the clinic due to lack of effect or to side effects. The most commonly reported positive effects were enhanced concentration, more overview, less restlessness, more stable mood, and having more energy. The principal reasons for discontinuing medication were anxiety/depression, cardiovascular complaints, and lack of effect.
Methylphenidate raised heart rate and lowered weight, but had no significant effect on systolic and diastolic blood pressure. Moreover, there was no significant correlation between methylphenidate dosage and any of these variables, nor between methylphenidate users taking hypertensive medication and those not taking such medication. There was no significant difference in systolic or diastolic blood pressure and heart rate before and after the use of methylphenidate among patients with the cardiovascular risk profiles.
Systolic blood pressure rose in ten out of 64 patients, with two experiencing an increase of at least 20 mmHg. It descended in five patients, with three having a decrease of at least 20 mmHg. Diastolic blood pressure rose by at least 10 mmHg in four patients, while dropping at least 10 mmHg in five others.
The authors concluded "that the use of a low dose of ADHD-medication is well tolerated and does not cause clinically significant cardiovascular changes among older adults with ADHD, even among those with an increased cardiovascular risk profile. Furthermore, our older patients experienced significant and clinically relevant improvement of their ADHD symptoms using stimulants, comparable with what is found among the younger age group," and that "the use of methylphenidate may be a relatively safe and effective treatment for older adults with ADHD, under the condition that all somatic complaints and especially cardiovascular parameters are monitored before and during pharmacological treatment."
Yet they cautioned that "due to the observational nature of the study and the lack of a control group, no firm conclusions can be drawn as to the effectiveness of the stimulants used. ... Important factors that were not systematically reported were the presence of other risk factors, such as smoking, substance (ab)use, aspirin use, and level of physical activity. In addition, the response to medication was not systematically measured"
Background
ADHD (Attention-Deficit/Hyperactivity Disorder) is one of the most studied neurodevelopmental conditions, with many clinical trials evaluating the effectiveness and safety of various medications. These trials, known as randomized controlled trials (RCTs), are considered the gold standard for assessing treatments. However, strict eligibility criteria often exclude many real-world patients, raising questions about whether the findings from these trials apply to everyday clinical settings.
Our latest study sheds light on this issue, revealing just how many individuals with ADHD might be excluded from RCTs and the impact this exclusion has on their treatment outcomes.
Method
Researchers used Swedish national registries to analyze data from 189,699 individuals diagnosed with ADHD who started medication between 2007 and 2019. They applied exclusion criteria from 164 international RCTs to identify who would have been considered ineligible for these trials in order to determine the proportion of individuals with ADHD who would not meet the eligibility criteria for RCTs.
Key Findings
Many Patients Are Ineligible for Clinical Trials:
Ineligible Patients Face Unique Challenges:
Higher Risk of Adverse Outcomes:
What This Means
These findings highlight a major gap between the controlled environments of clinical trials and the realities faced by individuals with ADHD in everyday life. While RCTs provide valuable insights, their restrictive criteria often exclude patients with more complex health profiles or co-existing conditions. This limits the generalisability of trial results, meaning that treatment guidelines based solely on RCTs may not fully address the needs of all patients.
Conclusion
This study demonstrated that a significant proportion of individuals with ADHD, particularly adults, do not meet the eligibility criteria for standard RCTs. These results emphasize the importance of bridging the gap between research settings and real-world applications. By recognizing and addressing the limitations of RCTs, we can work towards more equitable and effective ADHD treatment strategies for everyone.
Background:
Our understanding of Attention-deficit/hyperactivity disorder (ADHD) has grown and evolved considerably since it first appeared in the DSM-II as “Hyperkinetic Reaction of Childhood.” This study aimed to find the disorder’s placement within the modern psychopathology classification systems like the Hierarchical Taxonomy Of Psychopathology (HiTOP).
The HiTOP model aims to address limitations of traditional classification systems for mental illness, such as the DSM-5 and ICD-10, by organizing psychopathology according to evidence from research on observable patterns of mental health problems.. Is ADHD best categorized under externalizing conditions, neurodevelopmental disorders, or something else entirely? A recent study by Zheyue Peng, Kasey Stanton, Beatriz Dominguez-Alvarez, and Ashley L. Watts takes a closer look at this question using a symptom-focused approach.
The Study:
Traditionally, ADHD has been associated with externalizing behaviors, such as impulsivity and hyperactivity, or with neurodevelopmental traits, like cognitive delays. However, this study challenges the idea of placing ADHD into a single category. Instead, it maps ADHD symptoms across three major psychopathology spectra: externalizing, neurodevelopmental, and internalizing.
The findings reveal that ADHD symptoms don’t fit neatly into one box. For example, symptoms like impulsivity, poor school performance, and low perseverance were strongly associated with externalizing behaviors. On the other hand, cognitive disengagement (e.g., daydreaming, blank staring) and immaturity were closely linked to neurodevelopmental challenges. Interestingly, cognitive disengagement also showed ties to internalizing symptoms, such as anxiety or depression.
This research underscores the complexity of ADHD. Rather than treating ADHD as a single, unitary construct, the study advocates for a symptom-based approach to better understand and treat individuals. By acknowledging that ADHD symptoms relate to multiple psychopathology spectra, clinicians and researchers can move toward more nuanced classification systems and targeted interventions.
Conclusion:
Ultimately, this study highlights the need for modern systems to move beyond rigid categories and adopt a more flexible, symptom-focused framework for understanding ADHD’s place in psychopathology.
Exposure to heavy metals like lead, arsenic, mercury, cadmium, and manganese is known to harm developing nervous systems. However, past studies on whether heavy metals specifically increase the risk of ADHD have shown mixed results.
A research team from China (Gu et al., 2024) reviewed medical studies and conducted meta-analyses to better understand this issue.
The team included studies on children and teens, focusing on cohort studies, case-control studies, and cross-sectional studies. They only used articles written in English and required validated biomonitoring (like blood tests) to measure heavy metal exposure. ADHD diagnoses had to come from clinical evaluations.
To be included, studies had to report effect sizes such as odds ratios and relative risks with confidence intervals. The team focused on comparisons between groups with high, low, or no exposure, which made it harder to analyze dose-response relationships.
They also evaluated the quality of each study. All cohort studies were rated high-quality. Of the 15 case-control studies, 6 were high-quality, and 9 were moderate-quality. Among cross-sectional studies, only 2 were high-quality, and the rest were moderate-quality.
There was no evidence linking ADHD to other heavy metals like arsenic, mercury, cadmium, or manganese. Both meta-analyses suggest that lead exposure is associated with the risk for ADHD. However, because these studies cannot rule out other explanations, one cannot conclude that lead exposure causes ADHD. For example, other work shows that people with ADHD are likely to have lower incomes than those without ADHD.
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