ADHD in adults: despite evidence sufficient to guide diagnosis and treatment, many questions remain

Many readers will appreciate Cortese et al's review of attention‐deficit/hyperactivity disorder (ADHD) in adulthood ¹ . Considerable ground is covered, providing practical recommendations for health care professionals, such as using a provisional diagnosis when symptoms are present in only a single context, and how and when to make use of neuropsychological assessment. There is a thoughtful discussion of impairment and whether it should be based on general population performance benchmarks versus individual capacity. Representation of the views of people with lived experience of ADHD is noteworthy. Here I expand upon a few points that, in my opinion, require further discussion.

Concerning assessment, I would like to elaborate on the measurement of impulsivity in ADHD. The authors correctly report that studies have shown decline in the symptoms of impulsivity‐hyperactivity in samples followed longitudinally. However, impulsivity is a complex, multifactorial construct ² , that is poorly reflected in the three relevant DSM‐5 symptoms. For example, the UPPS‐P Impulsive Behavior Scale ³ includes five domains of impulsivity, and most factors – in particular, negative and positive urgency, premeditation (lack of), and perseverance (lack of) – are elevated in individuals with ADHD ⁴ . Thus, including only three items in rating scales, even when adjusted for adults, might underestimate impulsivity in adults with ADHD. Future research and clinical care may address this possibility with expanded measurement.

On the topic of prevalence, individual and cultural differences in acceptance of mental health diagnosis and treatment approaches are important to consider. The lower prevalence of ADHD amongst minoritized groups (e.g., Black and Latine people in the US) is likely to be the result of reduced access to care. However, we should also consider that cultural (as well as spiritual and philosophical) differences also drive personal constructions of mental health ⁵ . It is important to recognize the myriad ways in which mental health is conceptualized across individuals and cultures as we expand diagnosis and treatment globally. Understanding the mental health trajectories of individuals with satisfying lives who otherwise would have met DSM‐5 or ICD‐11 diagnostic criteria for ADHD could be enlightening.

On a related note, clinicians routinely wrestle with determination of impairment when diagnosing ADHD in the absence of serious consequences such as failing grades in university or employment performance warnings. Distress from failure to match performance with perceived capacity, such as inability to take on expanded responsibilities in personal and work life, are common and can lead one clinician to diagnose ADHD while another clinician will disagree. This diagnostic challenge is also relevant for older people when it might be easy to dismiss ADHD as a cause of distress in the absence of employment. However, I recommend that we consider the diagnosis of depression as a comparator. In that case, we respect and assess personally experienced distress as a cause for recommending intervention – be it pharmacologic or not. This is also where collateral informant reports have value, and where skilled clinical interviewing can separate mild, situationally specific symptoms from chronic, truly impairing experiences.

Concerning neuropsychological testing, the authors clarify that it may be helpful for identifying an individual's cognitive strengths and weaknesses and perhaps for ruling out other causes of apparent ADHD symptoms such as traumatic brain injury or emerging dementia. Neuropsychological testing is not recommended as useful in ADHD diagnosis. Interestingly, neuropsychological test batteries generally include, in addition to assessments of general intellectual ability and achievement, tests of working memory, attention and executive function, all domains frequently impaired in adults with ADHD. When test performance is poor, resulting clinical recommendations may be similar to those provided by a therapist using cognitive‐behavior therapy for ADHD to address the same deficits identified in clinical interview. An example is performing work in a low‐distraction environment to improve sustained attention ⁶ .

On the topic of ADHD course throughout life, more investigation is needed. A limited number of studies has shown that relatively few individuals with ADHD have a stable remitting course, but longitudinal research with successive measurements has only reached into the fifth decade of life ⁷ . In the Multimodal Treatment Study of Children with ADHD, rigorous prospective examination from childhood reached to a mean age of 25 ⁸ . Research into older adulthood is critical to understand how ADHD intersects with the aging process cognitively and physically. In addition, taking life course fluctuations into account in studies of the neurobiology and genetics of ADHD is critical. Relying on single point‐in‐time assessments of ADHD risks missing important biologically determined differences between individuals with different lifespan courses.

The authors refer to the extensive literature reporting the adverse health outcomes associated with ADHD. Successful health self‐management requires skills, planning, delay of gratification (resisting societally reinforced unhealthy food and drink consumption), and resources (e.g., access to healthy food). Therefore, it is not surprising that individuals with ADHD have poorer health outcomes, and simple provision of education is unlikely to drive improved outcomes. One key question for research is whether ADHD‐related health risks are specific to this condition or reflect a process of physical health deterioration following mental health difficulties more broadly. Cortese et al touch on this latter possibility by noting the prevalence of co‐occurring psychiatric conditions that may mediate the relation between ADHD and somatic conditions (e.g., alcohol use disorder leading to liver disease).

Finally, on the topic of treatment of ADHD in adulthood, the authors provide a helpful review of the status of the literature. My hope is that readers will not stop at the first sentence identifying pharmacological treatment as the cornerstone of management of adult ADHD. Certainly, efficacy of this treatment has been demonstrated, and a balanced discussion of treatment options follows where readers will notice that, in addition to the demonstrated efficacy of medication, there are additional factors to consider when forecasting long‐term treatment needs.

Now that we understand that ADHD is often a lifelong disorder, with variable expression, severity and impact, health care practitioners must integrate this understanding into their discussions with patients proactively. Although helpful, medication does not cure ADHD. Troubling non‐symptom aspects of ADHD are often not satisfactorily improved with medication and are likely to require periodic and/or sustained support with psychotherapy or other interventions throughout life, in accordance with individual need. In this respect, it is surprising that research on ADHD coaching remains in its infancy.

In a population‐based cohort study in the Netherlands, less than 20% of adults followed over 25 years were able to maintain healthy lifestyles across five critical behaviors (physical activity, body weight, smoking, sleep, and alcohol consumption) ⁹ . If maintaining a healthy lifestyle is hard for the general population, it will be especially difficult for individuals with ADHD to follow recommended behavioral changes. Successful long‐term care may need to include supports such as case managers embedded within routine clinical care settings to help patients maintain motivation and access available resources.

We have amassed sufficient literature and clinical experience to know that ADHD in adulthood exists. We should now turn our attention to the many questions, such as understanding lifespan trajectories, to inform our next steps in research and clinical care.