Introduction

Attention-deficit/hyperactivity disorder (ADHD) is a neurobehavioral condition characterized by symptoms of impulsitivity, distractibility, and impaired concentration stamina. ADHD is present throughout the lifecycle and is associated with significant functional and emotional impairment.1,2 When studied in all other age groups, ADHD demonstrates a consistency of epidemiology and prognosis that would predict similar findings in older adults.3 However, while very little is known regarding prevalence rates, morbidity, and prognosis of ADHD in adults over age 45 years,4 clinical experience supports the occurrence of persistent ADHD in older adults. Adults over age 45 have been included in ADHD clinical psychopharmacology trials,5 and adults in their 50s, 60s, and beyond are presenting for evaluation and treatment in our ADHD clinic.

Core ADHD diagnostic features of older adults are similar to younger adults; however, there is a profound paucity of data to guide clinicians assessing older patients with ADHD. Studies examining ADHD beyond childhood indicate that ADHD prevalence rates decrease with age, and that persistent ADHD is associated with less hyperactivity but ongoing executive function deficits.6,7 Overall, adult ADHD prevalence has been estimated at 4% based on community epidemiology studies6,8 (Figure9). The first large-scale epidemiologic study of psychiatric disorders including adult ADHD as a screened diagnosis excluded adults over the age of 45, citing “concern of recall failure among older adults.”8

This article presents two cases of ADHD in older adults, accompanied by a discussion of observed clinical aspects of this condition that highlight this demographic group in need of further research.

Case I

A 74-year-old retired physician, Dr. B, presented to the clinic “for an ADHD evaluation,” reporting lifelong difficulties with organization and distractibility. He was attempting to study genealogy and write a memoir. (Coincidently, his spouse had announced her “retirement” from organizing the patient and his new pursuits.) He reported that his papers were scattered around his office and that the home computer was “strangled with viruses and lost files.” His goal for treatment was improved reading comprehension and improved organization.

In school, Dr. B had been considered very bright. However, while achieving high grades on exams, his overall grades were consistently average because “I could never get the homework done or back to the school.” He attributed his school success to a relative outside of his immediate family who maintained frequent contact with instructors and encouraged them to “challenge me and keep me busy.” College was described as very difficult, requiring exceptionally hard work to maintain a B average.

Medical school was extremely challenging and all-consuming for Dr. B. Following residency, he went into private practice and considered himself successful, in large part because his nurses were eventually trained to surround him with a structured environment (for example, 6:00 AM reminder calls for a 7:00 AM meeting). His non-ADHD spouse kept him organized at home.

A psychiatric review of systems was negative for additional comorbidity. Dr. B had a history of coronary artery bypass, aortic abdominal aneurysm repair, hypertension, and hypercholesterolemia. A recent medical exam was completely normal, including blood pressure. Several adult children and one grandchild were currently being treated for ADHD.

On mental status exam, Dr. B was very pleasant, self-effacing, and affable, with normal motor control and intact short-term, intermediate, and long-term memory, and his vocabulary indicated a clearly superior IQ and fund of knowledge.

Based on a lifelong history of symptoms of disorganization, time-management problems, misplacement of objects, procrastination, incompletion of tasks, distractibility, and collateral confirmation by others, the patient met criteria for ADHD, inattentive type.
A trial of modafinil was prescribed. After several months, Dr. B felt that he had experienced little benefit and requested a trial of stimulants. Dextroamphetamine slow-release spansules were gradually titrated to 20 mg 2 times per day. This regimen has continued for 4 years, with significant improvement in organization, sustained focus, and reading comprehension. The patient still struggles with time management and has expressed concern that it takes him longer to recall information.

Case 2

A 61-year-old female, Mrs. W, was referred by her primary care physician for evaluation of treatment-resistant depression and possible ADHD. She had been treated for depression for more than 2 years but never noticed benefit. She attributed most of her low moods to frustration associated with incompletion of tasks. She enjoys reading but takes a long time to get through material. She endorsed disorganization, noting that “I can’t get things to happen, can’t get things done, things are piled up.” Managing time is difficult, and she cannot judge the amount of time necessary to finish tasks. She misplaces items and is chronically inattentive; the running joke with her spouse is that she constantly forgets what he tells her. She procrastinates and avoids detailed work, and described her house as “a disaster.” Her goals for treatment are “to get stuff done,” particularly keeping up her home.

Mrs. W hated grade school “from day one.” Never a discipline problem, in elementary school she felt she was an average student, but school increased in difficulty as the years passed. Teachers consistently considered her an underachiever, and she had no encouragement from school or family. By eleventh grade, her poor progress frustrated both the patient and her mother so much so that upon reaching age 16, she immediately dropped out of school and got a job. She recognized that “I’ve probably had ADHD all my life,” when years prior to her evaluation her youngest son was diagnosed with ADHD in second grade.

Mrs. W described her mood as “pretty much down” and endorsed anhedonia, yet she attributed both to chronic frustration. She reported normal sleep and appetite and no history of suicidal thoughts. She endorsed minimal anxiety but denied any symptoms of other psychiatric disorders.
Past treatments managed by the primary care physician included citalopram and duloxetine for 1 year each and a brief trial of bupropion, which caused dizziness. Mrs. W was in good health and taking no medication. Family history included her aforementioned son with ADHD, who had dramatically improved with methylphenidate. She speculated that her father had had ADHD, but there was no other family history of psychiatric disorder. Mrs. W was a night shift worker at a department store, and was happy in her second marriage of 25 years.

On mental status exam, the patient was calm and motor activity was normal. Mood was reported as “ok” and affect was euthymic. Immediate, intermediate, and long-term memory was intact. Vocabulary indicated an average IQ and normal fund of knowledge.

Based on significant underachievement in childhood and adolescence, and persistent impairment of attention in adulthood accompanied by disorganization, impaired time management, misplacement of objects, and task incompletion, the diagnosis was ADHD, predominantly inattentive type. Childhood history of learning problems (suggestive of learning disability) were considered attributable to ADHD, and learning difficulties were not identified by Mrs. W as a current functional concern or cause of distress. Although treated for depression in the past, she clearly did not meet criteria for a mood disorder, and mood symptoms were judged to be highly likely due to chronic discouragement associated with ADHD.

Methylphenidate 10 mg every 4 hours was prescribed, and 2 weeks later Mrs. W reported doing well; blood pressure was 150/90 and pulse was 80. However, she desired greater reduction in ADHD symptoms. Therefore, she was switched to mixture of dextroamphetamine salts 15 mg 3 times per day. At the next follow-up visit she reported that the medication was controlling her symptoms well, particularly her ability to complete goals without distraction. Mood was reported as “real good,” blood pressure was 120/85, and pulse was 75. At her most recent follow-up, she has continued on her medication for 8 months, vital signs have remained normal, and she reports good mood and limited impairment from ADHD symptoms.

Adult ADHD Diagnosis

ADHD at any age is a clinical diagnosis based on patient interview and collaborating information when available. The Diagnostic and Statistical Manual of Mental Disorders, 4th edition, Text Revision (DSM-IV-TR) describes four subtypes of ADHD: (1) Predominantly Hyperactive, (2) Predominantly Inattentive, (3) Combined Hyperactive and Inattentive Type, and (4) ADHD Not Otherwise Specified.10 While DSM-IV-TR can be used to diagnose adults, certain aspects of these criteria (originally intended for children) are problematic: in particular, the presence of hyperactive symptoms and evidence of the disorder before the age of 7.

Faraone et al11 have shown that adults with “late-onset” ADHD (ie, no symptoms before age 7, but otherwise chronic and persistent ADHD symptoms) are more similar than different from those patients meeting full DSM-IV-TR ADHD criteria. Based on our experience in both general psychiatry and ADHD clinics, clinicians encountering patients with characteristics listed in the Table should consider screening for ADHD. Additional screening tools can be helpful in diagnosis; one example used extensively and gaining acceptance as a valid component of evaluating adults for ADHD is the 18-Question Adult ADHD Self-Report Scale (ASRS). This scale and a smaller 6-Question Screening Scale are available for unrestricted use at www.hcp.med.harvard.edu/ncs/asrs.php.12,13

Adults with ADHD report a significant amount of anxiety symptoms that will not meet threshold criteria for a specific anxiety disorder; as Case 2 illustrates, the older adult with ADHD can present with complaints often associated with anxiety or mood disorders. Such symptoms may, in fact, be the result of discouragement and frustration associated with lifelong functional impairments of ADHD.14 Clinicians must also consider that a very high percentage of adults with ADHD have comorbid psychiatric disorders, in particular anxiety and depression.2 Many adults with ADHD are treated for their comorbid psychiatric disorders; few adults with ADHD are diagnosed or actively treated specifically for ADHD.8

Differential Diagnosis

It is important to view the broadest possible picture of cognitive function when evaluating older patients for ADHD. In patients over age 45 years, additional factors associated with aging and changes in executive dysfunction should be considered. These include increased incidence of other medical disorders resulting in impaired memory and attention, such as cerebrovascular disease, major depressive disorder, cumulative effects of substance use disorders, and dementia syndromes. Executive dysfunction very similar to ADHD can be seen in these conditions and should be considered in the differential diagnosis.15 Attention and memory problems are also associated with numerous medications that may be prescribed for other conditions.16 The patient’s entire cognitive history must be taken into account, referenced to current functioning and contrasted with increasing evidence of declines in aspects of attention associated with normal aging.17-19 Collaborating sources—such as childhood report cards and interviews with significant others—can be extremely useful in characterizing ADHD symptoms over time.

Clinical Considerations

In a comprehensive review of neuropsychological findings of ADHD across the lifespan, Seidman4 emphasized a fundamental finding in ADHD as persistent dysfunction of the executive system, a finding confirmed by Biederman and colleagues.7 The functional difficulties that persons with ADHD encounter, therefore, are immediately relevant to their current age-related environment (ie, grade school for the 7 year old, retirement for the 77 year old). Also specific to geriatric patients are cumulative consequences of ADHD.

Education and Vocational Challenges

Adults with ADHD typically underachieve with regard to education levels,1 and older adults who seek new careers face steep learning curves to develop technical skills. Ongoing education after hire is increasing. Adults with ADHD face similar job challenges at all ages—untreated, they are frustrated in attempts to maintain focus while engaged in tasks such as attending orientations, reading instruction manuals, or attempting computer-based learning. For some older adults with ADHD, a cumulative outcome from years of frustration in education and learning is avoidance of the workplace, refusing to be “set up to fail” or to be frustrated again. They choose to permanently withdraw from the workforce.

As Case 1 also illustrates, some adults view retirement as an opportunity to develop new interests. These may tax such cognitive skills as reading comprehension or computer skills. Without additional structure and/or the expectations of workplace organization (emphasizing punctuality, efficiency, and teamwork), many adults with ADHD report goals for later-life avocations clashing with an inability to maintain sustained attention.

Adults with ADHD are often underemployed and earn less than adults without ADHD.1 ADHD-associated problems are likely to become an increasingly important issue as economic and social factors extend the years that adults will work. As a consequence of lifelong struggles with ADHD, older adults enter the later stages of their careers with two frequently observed issues: (1) the immediate functional difficulties interfering with job performance as a result of ADHD, and (2) the cumulative effect of a working career marked by a checkered resume, underachievement, and lower income. In the end, cumulative vocational impairment leaves many older adults with ADHD in a demoralized and financially precarious position.

Social Struggles

Studies show that from an early age, children with ADHD symptoms struggle with social relationships. At home, these children are frustrated—and frustrating—with forgetfulness and disorganization; at school and outside of school, children with ADHD, in general, have more difficulty establishing peer relationships. Similar studies have revealed significant impairment in social skills of adults with ADHD.20,21

Older adults with ADHD report an ongoing sense of social shame. They chronically struggle with missing or always being late to engagements, distractibility in social settings, impaired word finding when communicating by phone or in person, and lost correspondence. Patients report that they have earned the unwanted reputation of being socially unreliable. Cumulative social consequences can result in older adults with ADHD simply withdrawing from social activities rather than risk further failure to meet social commitments.

Adults with ADHD are at higher risk for divorce.20-22 Married older adults with ADHD are often painfully dependent on a spouse or child to organize them. Those older adults who remain married are often in a position of feeling parented—more than partnered—with their spouse, resulting in mutual longstanding feelings of resentment. The death or infirmity of the non-ADHD spouse can be overwhelming to the individual and to the family that has to step in to take over organizational responsibilities.

Efficacy of Pharmacologic Treatments

Current literature supports the use of medication as an important treatment of ADHD for all ages.5,23 Currently, four stimulants are approved by the Food and Drug Administration (FDA) for treatment of adults with ADHD: mixed salts of a single-entity amphetamine product extended-release capsules, methylphenidate hydrochloride oral extended-release tablets, lisdexamfetamine and dexmethylphenidate hydrochloride extended-release capsules. The norepinephrine reuptake inhibitor atomoxetine is also approved for adults.

In clinical practice, stimulants and nonstimulant medications not approved by the FDA are also used to treat adult ADHD.24 No studies have been published examining efficacy of ADHD medications in patients age 45 years and older, although as noted previously, general adult ADHD pharmacology investigations include patients over age 45. In our experience, medication treatment response in older adults is equally robust to that seen in children, adolescents, and young adults. We believe that cognitive therapy is also effective, although studies using cognitive therapy have yet to include older adults.25

Safety of Pharmacologic Treatments

There are few reports addressing the safety of ADHD medication administered to older patients. Older adults are more prone to chronic medical problems and more likely to be taking other medications; therefore, treatment of older adults for ADHD may pose increased medication risks.

Stimulants and atomoxetine are associated with elevation in blood pressure and heart rate in persons at all ages, but the incidence of significant increases are small.26 Wilens et al27 conducted a 6-week open-label study of 13 adults with controlled essential hypertension and ADHD who were administered mixed amphetamine salts, demonstrating that these patients could be safely treated. However, older adults with essential hypertension may be at higher risk for persistent elevation in blood pressure. Amphetamines are indirectly acting sympathomimetics that trigger the release of norepinephrine, which may precipitate vascular spasm, indirectly inducing pharmacologic coronary vasoconstriction28; therefore, older adults with coronary artery disease taking stimulants may be at higher risk for myocardial infarction. There is a very limited literature describing adverse cardiac outcomes directly attributable to prescription stimulants in persons of all ages.28

The FDA recently advised that all individuals being considered for ADHD medication be screened for underlying cardiac disorders and family history of sudden cardiac death.29 The FDA has also initiated an extensive database review to evaluate cardiovascular safety of ADHD medications in children and adults.30

Glaucoma is a relatively rare disorder in younger adults and increases in prevalence with age. The use of stimulants and atomoxetine in glaucoma is contraindicated. Patients over age 45 should have a comprehensive eye exam within the previous year before considering the use of ADHD medication.31

Stimulants have been used in treating the elderly for a variety of disorders, and there is an extensive literature over the past 60 years describing a clinical experience indicating that these medications are generally safe and lack evidence of abuse.32,33 However, there are no long-term data evaluating outcomes of older adults taking maintenance medication specifically for ADHD.

Risks of Untreated ADHD

What are the risks of not addressing ADHD in older adults? Able and colleagues34 compared controls to adults with undiagnosed and diagnosed ADHD, and reported significant functional and psychosocial impairment in adults with undiagnosed ADHD. Missed office visits, forgetting to reschedule visits, and “just forgetting” to follow-up as directed is a common finding and has been reported by other adult ADHD clinics.35 Recent data indicate that ADHD, in general, may be associated with reduced life expectancy.36 Because aging patients with chronic conditions require more contact with the healthcare system, those with untreated ADHD may be at greater potential risk for adverse medical outcomes. For example, medication adherence can be compromised as many older adults with ADHD have great difficulty consistently administering even one pill every morning. In our experience, older adults take better care of all medical conditions when successfully treated for ADHD.

Conclusion

Increasing evidence indicates that impairment from ADHD symptoms can be lifelong; clinical experience indicates that older patients with ADHD present with symptoms similar to those of younger patients and respond equally well to treatment.
ADHD can also exhibit a unique negative cumulative impact on adults over age 45. Despite the significant consequences of ADHD, few adults of any age receive any treatment for ADHD, including those adults with ADHD receiving mental healthcare for other conditions.

Further research is needed to evaluate the epidemiology and natural history of older adults with ADHD and associated comorbid conditions. While the safety and tolerability of stimulant medication is generally established for other disorders in older adults, there are no data on long-term use of stimulants prescribed specifically for ADHD. Similarly, preliminary studies using cognitive-behavioral therapy for adult ADHD need to be expanded to include older adults. Specific screening algorithms are unavailable for evaluating cardiovascular risks of stimulants in older adults with comorbid cardiovascular conditions. As subtle universal changes of executive function associated with normal aging are better characterized, more objective measures are needed to incorporate these changes into assessments of cognitive performance, and distinguishing what qualifies as ADHD, normal aging, early dementia, or contributions from more than one of these processes.

Dr. Wetzel has received speaker honoraria from Cephalon, Inc, Forest Laboratories, GlaxoSmithKline, Eli Lilly and Company, Jazz Pharmaceuticals, Shire Limited, and Wyeth Pharmaceuticals. Dr. Burke has received research grant support for clinical trials from National Institutes of Mental Health, National Cancer Institute, Eli Lilly and Company, Novartis Pharmaceuticals, McNeil Pediatrics Division of McNeil-PPC-Inc, Cephalon, Inc, Forest Research Institute, Merck & Co, Inc., Voyager, Somaxon Pharmaceuticals, and GlaxoSmithKline, and has received speaker honoraria from Forest Laboratories.