Advances in ADHD Management: Adult ADHD and Comorbidities

The high risk for comorbidity in patients with ADHD means that symptoms of other conditions are often more prominent than ADHD symptoms in clinical encounters with these patients. Comorbid conditions can obscure manifestations of ADHD, both because their symptoms may overlap with those of ADHD and because these other conditions may be so impairing that individuals are unable to participate in activities that would demonstrate ADHD challenges. To identify ADHD as often as possible, providers must be aware that ADHD can lie beneath a broad range of chief complaints.

There has been little systematic investigation of how to optimize identification or treatment of ADHD in the context of a current comorbidity. This article offers some recommendations in regard to aspects of clinical assessment and treatment planning that may be useful in addressing comorbid conditions in adults with ADHD. Because space limits full exploration of all conditions that can co-occur with ADHD, after considering general principles, this article focuses on considerations relevant to addressing anxiety comorbidity. However, the principles explored here have application to the identification and management of many comorbid conditions.

Evaluating Patients With ADHD and Comorbid Disorders

Many newly diagnosed adults with ADHD report that they were previously evaluated by mental health professionals and treated for other mental health disorders, and that despite its presence ADHD was not identified in these clinical encounters. This may, in part, be because other mental health conditions obscured or distracted from ADHD symptoms. Clinicians may improve the chances of identifying an adult ADHD diagnosis by actively inquiring about ADHD symptoms in a way that is sensitive to the impact of these symptoms, and the difference between the impact of these symptoms and that of comorbid disorders.

Unless patients present with a specific concern that they have ADHD, active interviewing may be the only way that a clinician identifies the presence of the condition. Interviewing patients about mental health symptoms that they do not report is essential to identifying a number of mental health conditions. However, ADHD stands out from some other Axis I disorders in that it is a syndrome defined by its impact on functional pattern, with no requirement of emotional symptoms. Because the disorder affects functional patterns, asking questions, such as "What kinds of tasks or assignments have been hard for you in school or work?" is useful.

Although impulsivity and hyperactivity may be present in some adults who meet the criteria for ADHD, the prevalence of these traits declines with age, and adults with ADHD are more likely than children to have the inattentive rather than combined or impulsive-hyperactive subtypes. Adults are also likely to have developed compensatory strategies, which themselves may be burdensome. These characteristics of adult ADHD mean that it is quite important when assessing adults for ADHD to learn about a patient's cognitive challenges or cognitive style, such as how well they can pay attention, organize, and remember, rather than relying on an assessment of behavior alone. Although cognitive impairment may not be the presenting complaint, a comprehensive psychiatric assessment should include efforts to understand a patient's chronic cognitive challenges. Systematically asking not only about the DSM-IV symptoms of ADHD, but also how much effort it takes individuals to avoid problems associated with these symptoms, is a useful approach (for example, asking how much effort and time are involved in keeping track of items, how carefully people have to use organizational strategies, how much of a strain is it to pay attention).

Adults with ADHD who present in emotional or anxiety distress often directly attribute their current distress to ADHD-related problems in their academic, work, or social life. However, even after adults with ADHD have learned how ADHD traits have contributed to their difficulty performing up to their own and other's expectations, many report that it is hard to tell whether current mental health distress is related to traits of the disorder.

In some cases, current comorbid states are too impairing to determine whether ADHD is co-occurring. Because ADHD is a chronic condition by definition, it may be useful to identify how individuals functioned during periods of better mental health in the past. In many cases, the onset of ADHD occurs before other disorders. In some patients, such assessment may be more feasible after the most prominent source of distress is managed.

Among the DSM-IV conditions that commonly co-occur with ADHD, some are of relatively higher importance to identify before initiating ADHD treatment.^[4,5] For example, a history of psychosis or mania, which can be exacerbated by stimulants, should be addressed before tackling ADHD. Likewise, a recent history of substance abuse may make nonstimulants the preferred treatment and will also mandate certain nonpharmacologic interventions. Clinicians should thus be careful to identify not only current comorbidity, but also past, because of the potential for predisposition to poor ADHD treatment response to pharmacotherapy with an ADHD agent alone.

Which Condition Should Be Treated First?

As stated, very little scientific evidence exists to guide a clinician's choice of how to prioritize treatment. However, because the relative impairment associated with ADHD is often less than that associated with other mental health conditions, it is clinically prudent to prioritize many other Axis I disorders over ADHD. Although it may be tempting to start multiple treatments simultaneously, this approach obscures which intervention is producing which effects, and limits empirical interpretation of response to treatments.

Many clinicians have found it useful to undertake treating the most impairing condition first, and pediatric treatment guidelines recommend this approach.^[6,7] Thus, milder states of anxiety or mood distress that are not robustly impairing would be deferred until after ADHD management has been established. Indeed, patients sometimes report that the very process of being diagnosed and treated for ADHD reduces their emotional distress and obviates the need for treatment of those comorbid symptoms. Very few studies have included management of comorbid conditions in adults with ADHD, but clinical trials for ADHD often include patients with mild-to-moderate mood or anxiety distress who tolerate drug exposure well (for example, Hamilton Rating Scale for Depression [HRSD] < 15, Hamilton Rating Scale for Anxiety [HAM-A] < 15).

When deciding whether to address ADHD or a comorbid condition first, it may be useful to explore which is more impairing in the patient's recent life experience. Patients may tolerate such a stepwise approach to their concerns if the clinician discusses the risks and benefits of establishing the hierarchy and of alternate strategies. Because some comorbid conditions take substantial time or multiple trials to resolve, the process may be trying for some patients. This may be particularly true of patients with impulsive traits; such individuals can have particular difficulty sticking with treatment plans. Patients may stay better engaged in a comorbidity treatment plan if they are regularly reminded that treatment of comorbidity may facilitate a successful ADHD treatment in the future.

Addressing ADHD and Comorbidity: Focus on Anxiety

The NCSR found that, in the year before the survey, 47.7% of adults who met the criteria for ADHD and 19.5% of adults who did not meet the criteria for ADHD also met the criteria for an anxiety disorder. The most common subtypes of anxiety identified in the survey were social phobia (29.3%), specific phobia (22.7%), and posttraumatic stress disorder (11.9%).^[3] Differentiating anxiety and ADHD syndromes can be challenging given the overlap in symptoms between the 2 kinds of disorders. When the 2 coexist, it may not be possible to answer the question of whether anxiety symptoms are caused by or independent of ADHD.

Preoccupying worry may limit a patient's ability to concentrate, process information, and respond flexibly/efficiently to daily tasks, and these are traits that also appear in ADHD. Individuals may also be physically restless either because of anxiety or ADHD: Fidgeting and pacing are common characteristics of both syndromes. Tasks may not be accomplished because of procrastination if they require effortful attention, as is typical in ADHD, or because of avoidant behavior associated with phobias. Some adults with ADHD are quite self-conscious about circumstances in which their ADHD traits cause challenges or embarrassment. Some patients describe feeling afraid that they won't be able to control their ADHD traits in social situations; what at first sounds like social phobia may actually be fear of social manifestation of ADHD.

To distinguish between anxiety and ADHD as a cause of purported ADHD traits, it is useful to explore the patient's conscious thought process during the situations when the traits manifest. For example, anxiety may lead someone to report that they are so preoccupied with worry that they can't pay attention in conversations, meetings, or while studying. By contrast, a patient with ADHD who does not have prominent anxiety is more likely to report that their distracting thoughts lack anxious themes. Another helpful strategy for identifying ADHD as a cause of anxiety is to ask patients whether it takes mental effort to control their attention in situations that make them anxious. For example, is it prohibitively difficult to organize the components of a presentation that they are nervous about or keep track of what individuals are saying in meetings they fear?

When symptoms of ADHD and anxiety have been identified, many patients with anxiety disorders, particularly manifestations that are subthreshold for a full diagnosis, report that they cannot identify whether ADHD or anxiety is more impairing. When an anxiety disorder is not the clearly prominent cause of functional impairment, it may be useful to consciously separate performance-related anxiety (for example, worry about being able to complete tasks, organize life, and remember important obligations) and nonspecific anxiety (generalized catastrophic thinking, worry about what might happen in the future, and how situations out of their control will resolve), and attribute the performance-related symptoms to ADHD, as part of assessing whether it is the most impairing condition.

No systematic prospective studies have assessed methods of treating adults with ADHD who have comorbid anxiety disorders. In the case of individuals meeting the criteria for a full DSM-IV anxiety disorder that is a primary source of current impairment, the practical approach is to use the first-line, evidence-based treatments for those disorders before treating ADHD. Such patients should be reassessed for ADHD once their anxiety condition has been controlled because ADHD-like symptoms may actually have been related to the anxiety disorder. Studies are equivocal with regard to whether children with ADHD and anxiety disorders are less responsive to stimulant treatment than children with ADHD who do not have anxiety disorders. Although several studies have suggested that this is the case, at least 3 studies have not found an anxiety-moderating impact on the effect of stimulants.^[8-10]

A study of atomoxetine treatment in children with anxiety disorders and ADHD found more improvement in anxiety symptoms after treatment with atomoxetine relative to placebo administration.^[11] The effect size of anxiety reduction attributable to atomoxetine was only 0.5 in this study, whereas the effect size for ADHD improvement was twice that. Although atomoxetine monotherapy is reasonable for patients with ADHD and mild anxiety distress when both are an important target, stimulant treatments are often tolerated very well in the setting of mild anxiety. Because of their greater apparent effect sizes in clinical trials for ADHD, stimulants remain the first-line treatment for uncomplicated ADHD.^[12]

Psychotherapies are not a first-line treatment for uncomplicated ADHD; however, these techniques provide significant benefit for patients with anxiety and other comorbid conditions, and should be recommended for adults with ADHD who have such conditions. In diagnostically challenging cases, a multidisciplinary approach may provide more comprehensive assessment. No studies have been designed to assess the impact of multimodal therapeutics for adults with comorbid ADHD presentations. However, one study tracked anxiety in 31 adult subjects on stable pharmacotherapy for ADHD who did and did not receive cognitive-behavioral therapy for ADHD. Individuals who received cognitive-behavioral therapy, which was focused on developing organizational skills, reported lower anxiety scores as reflected in the HAM-A and Beck Anxiety Inventory (P < .04).^[13] This finding suggests that nonpharmacologic interventions for ADHD can meaningfully address comorbid distress.

Patients should always be counseled that psychotropic treatments sometimes produce worsening of mental health states. All ADHD treatments are to some degree sympathomimetic and may produce symptoms that mimic the physical manifestations of anxiety; for example, an internal feeling of "jitteriness," increased heart rate, or muscle tension are all reported side effects of stimulants. For some patients, caffeine appears to amplify these and other side effects, and it often is helpful to ask patients to cut down or stop caffeine during the initiation of ADHD pharmacotherapy to minimize side effects.

Clinical practice will benefit significantly from attempts to further delineate relationships between ADHD and comorbid conditions, and from clinical trials that address the management of complex ADHD presentations. Until clinical tools better facilitate objective differentiations of mental health conditions, clinicians must rely on careful and comprehensive interviews that are sensitive to the manifestations of ADHD and comorbid conditions. Future clinical trials may facilitate informed, evidence-based treatment choices, although the heterogeneity and complexity of comorbid presentations of ADHD in adulthood make it technically challenging.

This activity is supported by an independent educational grant from Shire.