Attention Deficit Hyperactivity Disorder in Adults Recognition and Management
J. Allen Scoggin, Pharm.D., MPA
Associate Professor of Pharmacy Practice and Pharmacoeconomics, University of Tennessee, College of Pharmacy, Memphis, TN
Attention-deficit hyperactivity disorder (ADHD) is considered the most common psychiatric disorder experienced during childhood.(1) Some references indicate an incidence as high as 10% of American school-age children. Most references, however, place the incidence in this age group at around 2%–5%.(2-4) Approximately 80% of children with ADHD continue to have symptoms of the condition as adolescents, and more than 60% of children experience symptoms as adults.(5) If these estimates are correct, between 2 and 5 million adults who had ADHD as a child continue to be affected by the condition. Many adults with ADHD have not been diagnosed as such.(6)
Potential Etiological Factors for ADHD
Small brain size and/or delayed
maturation of the brain(10)
Neurotransmitter deficiencies such as dopamine(3,10,11)
Reduced blood flow and electrical activity to the promotor cortex and prefrontal cortex of the brain—
areas involved in motor activity and attention(3,10,11)
Being a twin of a person with ADHD(11)
Rare thyroid disorder(11)
Environmental and Psychological Factors
Delivery of children by young mothers(3)
Delivery of low birth-weight children(3,11)
Maternal alcohol consumption(10)
Environmental toxins such as lead(10)
Drug-induced factors—seizure medications such as phenytoin(10)
Despite these findings, some physicians are reluctant to diagnose ADHD in adults, believing that the disorder is limited to childhood and probably vanishes with puberty, or at least subsides by the end of adolescence.(7,8) Many adults with ADHD may have been treated previously for depression, antisocial personality, or character disorders.(6) ADHD is often overlooked, particularly if the disorder was not identified when the person was a child.(5,8) Some adults may have avoided early detection due to the presence of a high I.Q., compliant behavior, or interpersonal charm.(8)
The exact cause of ADHD is still unknown.(3) It is unlikely that one single factor is responsible for all cases of ADHD.10,11 Barkley and other
researchers provide etiological possibilities that can be grouped into three major categories (TABLE 1). Barkley emphasizes hereditary, or genetic,
factors as playing the largest causative role in ADHD. He suggests that the tendency toward depletion of dopamine in the prefrontal, striatal, and
limbic regions of the brain, and the interconnections located in these areas may be transmitted genetically to a child who develops ADHD.(10)
Outcomes Associated with ADHD in Adolescents and Adults Personal Problems
Poor concentration. Many lose things easily (e.g., car keys, tools)(1)
Poor academic achievement. Many do not graduate from high school(4,5,9)
Low occupational achievement(9)
Low paying jobs. Research has shown that adults with ADHD are not highly unemployed. However, they do tend to hold lower positions on the occupational ladder.(9)
Restlessness and difficulty with sedentary-type work (e.g., desk jobs)(2)
Failure to listen to or understand instructions(6)
Oppositional behavior toward persons in authority(1,2)
Loss of jobs due to poor performance or attentional and organizational problems. Some quit jobs because of boredom(6)
Anxiety and mood swings(6)
High rate of substance abuse, especially alcohol and cocaine(1,4,5)
Antisocial behavior and problems with the criminal justice system(9)
Symptoms associated with adult ADHD include many of the same symptoms observed during childhood, except adults tend to have less problems with motor hyperactivity.8 Problems associated with adult ADHD can be grouped into personal, job-related, and psychiatric areas (TABLE 2). Many adults with ADHD feel demoralized and overwhelmed.(8)
Currently, ADHD is classified by the American Psychiatric Association into two categories based on symptoms that produce three distinct diagnostic types (TABLE 3). The three recognized ADHD types include a type in which inattentiveness predominates, a type in which hyperactivity or impulsivity predominates, and a combined type. Symptoms associated with each of these types must have been present prior to the age of seven and produce clear evidence of impairment in social, academic, or occupational functioning.(2)
Comorbidities and Diagnosis
Comorbidities commonly seen in children with ADHD include Tourette’s syndrome, learning disabilities, speech problems, depression, agitation, obsessive
compulsive disorder, and conduct disorders.(5,11) Comorbidities seen in adolescents and adults include agitated depression, hypomania, substance abuse, and antisocial personality disorder.(5)
Diagnosis of ADHD in adults is based on the same diagnostic criteria used for children. The adult must have experienced symptoms of the condition before age seven,2 and those symptoms must have occurred for at least six months and resulted in significant impairment in social and/or academic functioning.
Diagnostic Criteria for ADHD
I. Either (A) or (B):
(A) Six (or more) of the following symptoms of Inattention have persisted for at least 6 months to a degree that is maladaptive and inconsistent with
1. Often fails to give close attention to details or makes careless mistakes in schoolwork, work, or other activities.
2. Often has difficulty sustaining attention in tasks or play activities.
3. Often does not seem to listen when spoken to directly.
4. Often does not follow through on instructions and fails to finish schoolwork, chores, or duties in the workplace (not due to oppositional behavior or failure to understand instructions).
5. Often has difficulty organizing tasks and activities.
6. Often avoids, dislikes, or is reluctant to engage in tasks that require sustained mental effort (such as schoolwork or homework).
7. Often loses things necessary for tasks or activities (e.g., toys, pencils, books, or tools).
8. Often is easily distracted by extraneous stimuli.
9. Often is forgetful in daily activities.
(B) Six (or more) of the following symptoms of Hyperactivity-Impulsivity have persisted for at least 6 months to a degree that is maladaptive and
inconsistent with developmental level:
1. Often fidgets with hands or feet or squirms in seat.
2. Often leaves seat in classroom or in other situations in which remaining seated is expected.
3. Often runs about or climbs about excessively in situations in which it is inappropriate (in adolescents or adults, may be limited to subjective
feelings of restlessness).
4. Often has difficulty playing or engaging in leisure activities quietly.
5. Often is “on the go” or often acts as if “driven by a motor.”
6. Often talks excessively.
1. Often blurts out answers before questions have been completed.
2. Often has difficulty awaiting turn.
3. Often interrupts or intrudes on others (e.g., butts into conversations or games).
II. Some symptoms of (A) or (B) that caused impairment were present before age seven.
III. Some impairment from symptoms is present in two
or more settings (e.g., at school or work and at home).
IV. Clear evidence must be seen of clinically significant impairment in social, academic, or occupational functioning.
V. Symptoms do not occur exclusively during the course of a pervasive development disorder, schizophrenia, or other psychotic disorder and are not better accounted for by another mental disorder (e.g., mood disorder, anxiety disorder, dissociative disorder, or a personality disorder).
VI. The diagnosis can consist of three ADHD types:
1. Combined type: Criteria for both (A) and (B) have been met for the past six months.
2. Inattentive type: Criteria for (A) have been met but (B) has been met for the past six months
3. Hyperactive-Impulsive type: Criteria for (B) have been met but (A) has been met for the past six months
Source: adapted from reference (2)
Before the DSM-IV criteria were published, Fargason and associates provided characteristics of adult ADHD that may be useful to practitioners in making a diagnosis (TABLE 4).(4) Because there is no definitive test for ADHD, diagnosis must be made based on a clinical picture of the adult as a child; how that clinical picture has persisted over time, across different settings; and the degree of functional impairment present.(11)
Successful treatment of ADHD in children usually involves drug and nondrug therapies. Nondrug interventions for children include educational and psychosocial activities. A national organization called CHADD (Children and Adults with Attention Deficit Disorder) provides resources to parents and teachers.(6)
Adult Characteristics That May Indicate ADHD
Motor Hyperactivity: Restlessness, restless sleep
Attention Deficits: Inability to focus on written material,
Hot Temper: Outbursts, loss of control
Impulsive: Speaking without reflecting, lack of self-control
Stress Intolerance: Feeling overwhelmed
Nondrug programs for adults with ADHD are less developed. However, because poor self-esteem is common, individual counseling sessions that focus on changing maladaptive behavior, improving social and organizational skills, and handling anger in an appropriate manner are recommended. Vocational counseling, special tutoring, and deficit retraining for adults with learning disabilities may be beneficial.(4)
As with children, the mainstay of treatment for adults with ADHD is medication. Generally, the same medications that are used for children are effective in adults. However, adults seem to have more variability than children in their response to medications.5 There is some evidence that children who were treated with stimulants experience better outcomes as adults.(1)
Stimulants: Stimulants are considered the most effective medications available for adults, particularly when symptoms of ADHD related to cognition are present.(4) Adults tend to be more sensitive to both the therapeutic actions and side effects of stimulant drugs.(8) Dextroamphetamine and methylphenidate are considered by many to be the stimulants of choice, due to hepatotoxicity reported with pemoline.(12) In addition, pemoline has been reported to have a lower response rate in adults than the other two stimulants, except in the most strictly selected patients.4 However, pemoline offers one advantage: it has less potential for abuse and is not subject to the regulations that affect schedule II drugs such
as methylphenidate and dextroamphetamine.(13)
Methylphenidate is the most commonly prescribed of the stimulants, probably because of its balance of quick onset of activity, high efficacy, and minimal side effects.(4) Methylphenidate and dextroamphetamine share a similar pharmacology (both increase the release of norepinephrine and dopamine at nerve terminals) and efficacy.(12,13) Controlled studies indicate that up to 78% of adults respond favorably to stimulants, with similar responses reported for methylphenidate and pemoline.(7) Some researchers suggest that the dose of methylphenidate used in some studies (less than 0.6 mg/kg per day) may not have been high enough to evoke a desired response in adults.(7) With children, doses in the range of up to 150 mg/day for dextroamphetamine and 300 mg/day for methylphenidate have provided a higher level of symptom control than doses recommended in the Physicians’ Desk Reference and other publications.(14) However, since adults are more sensitive to stimulants than are children, the common dose range for methylphenidate in adults is 20–80 mg/day. Some adults respond adequately to only 2 mg/day.(8) The immediate acting form is often preferred because some adults cannot tolerate the excessive side effects from the sustained-release form, whose longer duration of effect may cause insomnia.(8)
Side effects of stimulants in adults are reported to be mild; they include insomnia, edginess, diminished appetite, weight loss, dysphoria, and headaches.(4) Cardiovascular side effects have been clinically insignificant, and there are no reports of abuse in adults from the use of stimulants for ADHD.(7)[underline added]
Nonstimulant Medications: Alternatives to stimulants are needed by many adults with ADHD for several reasons. Stimulants are not effective or well tolerated in about a third of adults, and they carry abuse potential. Their lack of 24-hour dosing creates the possibility for noncompliance. There may be a “rebound of ADHD symptoms,” especially with the short-acting stimulants. In addition, the rebound may be worse than baseline behavior.11 Lastly,
stimulants may produce variable patient response.4 Nonstimulants used for the management of ADHD symptoms in adults include antidepressants, beta-adrenergic blocking agents, and centrally acting antihypertensive agents.
Antidepressants: The tricyclic antidepressants (e.g., imipramine and desipramine) [underline added]offer several advantages over the stimulants, namely longer half-lives to allow for once-a-day dosing, no abuse potential, and the option of plasma level monitoring, if desired.(4,13) Imipramine has produced a high level of response in adults with ADHD, with some experiencing dramatic improvement. However, tolerance to this agent has been reported in some instances after two to three months of therapy.4 Open trials with imipramine in adults indicate that the tricyclic antidepressants may be preferred in patients with comorbidities such as anxiety and addictive tendencies.(13) However, serious cardiac side effects reported in a small number of children taking desipramine may necessitate monitoring (e.g., vital signs and EKG) when using tricyclic antidepressants in adults with a history of heart problems.(5)
Literature describing the use of selective serotonin reuptake inhibitors (SSRIs) in ADHD is limited. However, anecdotal reports indicate the SSRIs are not effective in reducing the core symptoms of ADHD.(5,8) The MAOI-type antidepressants are generally not used in ADHD due to orthostatic hypotension,
interactions with other drugs and certain foods, and the fact that the desired response may not be sustained with these agents.(8) Venlafaxine is an antidepressant that has shown promise in open trials in ADHD, but the incidence of side effects in one series of studies was considered too high.(8)
Bupropion is an antidepressant that works by a different mechanism than SSRIs or tricyclics and appears efficacious in ADHD at 5–6 mg/kg/day doses.11 Bupropion may have weak dopamine reuptake blocking activity, which could be beneficial in correcting the proposed pathophysiology associated with ADHD.(12) Response from the drug appears to be rapid and sustained.7 In one trial, bupropion was effective in adults with ADHD who formerly received stimulants.(13) However, until more studies are conducted, it should be considered a second-line agent for ADHD, especially if mood instability and/or cardiac abnormalities are present.(7)
Beta-adrenergic Blockers: The role of beta-adrenergic blockers in adults with ADHD is unclear. In a small study (13 patients) of adults taking up to 640 mg/day (528 mg/day was the average dose) of propranolol, temper outbursts improved in over 80% of those studied and the drug was well tolerated.(15)
Another report indicated that adding a beta-blocker to stimulant medication was helpful in three adults.(7) Nadolol at a dose of 20–40 mg/day is another beta-blocker that may be useful in managing adults with ADHD who have excessive excitability and overarousal.(4) Propranolol and nadolol have been used safely alone or in combination with stimulants.
Centrally Acting Antihypertensives: The centrally acting antihypertensives clonidine and guanfacine may be effective in ADHD if combined with other agents. When used with stimulants these agents may help control aggressiveness and hyperactivity in some patients.(4,11) Although clonidine has been shown effective in children and adolescents, it has not been evaluated in adults. Side effects (e.g., hypotension and sedation) may limit use of the drug in adults.(7) Currently, clonidine and guanfacine are considered third-line treatments for ADHD.(15)
Mood Stabilizers: Like the SSRIs, mood stabilizers such as lithium, carbamazepine, and valproic acid do not appear to have a positive effect on the core symptoms of ADHD.(11,15)
Unproven Therapies: A number of unproven therapies are reported (in the media and on the Internet) to be effective as memory stimulants and agents that could improve mental alertness and I.Q. Such claims are associated with hypericum, Ginkgo, pycnogenol, DMAE, the amino acid L-glutamine, and several Chinese herbal combinations. Until these and other ingredients have been evaluated in controlled studies to determine their efficacy and role in ADHD, it is premature to suggest an advantage for any of these.
For many, the symptoms of ADHD continue into adulthood. Although far more is known about this disorder in children and adolescents, it is being recognized more frequently in adults. For those adults with ADHD who cannot use stimulants, a variety of other medications are being tried. Experience with different pharmacologic therapies will, hopefully, give us a better understanding of their role in treating adults with ADHD.
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2. American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders. Fourth Edition. Washington. DC, American Psychiatric Association 1994;78-85.
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5. Dulcan MK, Benson RS. Summary of the practice parameters for the assessment and treatment of children, adolescents, and adults with ADHD. J Am Acad Child Adolesc Psychiatry. 1997;36(9):1311-17.
6. Children and Adults with Attention Deficit Disorders (CHADD) Internet Home Page (http://www.chadd.org) Available from Webmaster@chadd.org. Accessed 1998 March 13.
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14. Kessler S. Drug therapy in attention deficit hyperactivity disorder. South Med J 1996;89(1):33-8.
15. Spencer T, Biederman J, Wilens T. Pharmacotherapy of attention-deficit hyperactivity disorder across the life cycle. J Am Acad Child Adolesce Psychiatry. 1996;35(4):409-32.