Attention-deficit/hyperactivity disorder (ADHD) may be the only mental disorder that was discovered in children and later acknowledged in adults. Although controlled studies of adults with ADHD are few, we know that ADHD is common in adults, it can be diagnosed reliably, and 75% of those treated respond to treatment.1
The hallmark symptom of ADHD in children—hyperactivity—is usually attenuated in adults. In fact, some adults prefer the term ADD to ADHD because they are not hyperactive. This may be especially true of women, as their attention problems during childhood often were not recognized as ADHD (Box 1).
WHY ADHD IS OFTEN MISSED IN GIRLS
In childhood, girls with ADHD typically present with attention problems and over-talkativeness, rather than hyperactivity. Talking too much does not disrupt the classroom as much as the larger-scale misbehavior of boys with ADHD, so the diagnosis is often missed in these girls. Overtalkativeness was added to the DSM-III-R criteria for ADHD in 1987, after it was recognized as a symptom of overactivity.
Now in midlife, many women with undiagnosed ADHD have children with ADHD. As they bring their children to treatment, these women are recognizing similar attention deficit symptoms from their own childhoods and are getting the help they need. As adults, many have low self-esteem, low energy, and weight problems. Among adults with ADHD, these women may be the most underdiagnosed.
Characteristics of adult ADHD
Adults with ADHD visit a psychiatrist for a variety of reasons. Often they are parents of children diagnosed with ADHD, and the possibility that they are similarly affected has arisen during their children’s evaluation and treatment. Sometimes they have recognized themselves in consumer articles about ADHD, or others have seen them in this light.
Adults with ADHD continue to experience their childhood difficulties in sustaining attention, listening, following instructions, and organizing tasks; inattention to details; lack of sustained mental effort; losing things; distractibility, and forgetfulness. Typical complaints include underachievement and poor adjustment at work or home. Comorbid ADHD may also be identified in patients who present with depression, anxiety, substance misuse, and mood swings.
The cognitive impairment of ADHD continues into adulthood, even in adults without hyperactive symptoms. It may be that adults are not hyperactive because the basal ganglia, which control motor activity in the brain, have over the years accommodated the problem through behavior modification or neurodevelopmental changes in late adolescence.2
Children with ADHD have abnormal cerebrospinal fluid (CSF) and blood levels of the dopaminergic metabolite homovanillic acid (HVA), but adults with ADHD may not. The primary origin for CSF HVA is the nigrostriatum, which suggests that subcortical dopaminergic nuclei are more often affected in children than adults.2 This may mean that compensatory changes occur as persons with ADHD mature, or perhaps the forms of ADHD that persist into adulthood have a different pathology or pathophysiology.
Comorbidities with ADHD
Rarely does one see pure ADHD; comorbidity is the rule. ADHD can be diagnosed quickly if you know what to look for. But a facile diagnosis may overlook a comorbidity that must be treated first—especially if you plan to use stimulants. Many patients with ADHD also have bipolar disorder, and a smaller proportion of patients with bipolar disorder have undetected ADHD. Placing a patient with undetected bipolar disorder on a stimulant could precipitate mania.
Table 1
COMMON COMORBIDITIES WITH ADHD
| Bipolar disorder |
| Anxiety disorder |
| Depression |
| Drug dependence |
| Personality disorders |
| Somatoform disorders |
| Tourette’s disorder |
| Obsessive-compulsive disorder |
| Intermittent explosive disorder |
| Impulse control problems |
| Addictive behaviors |
| Sexual problems |
| Compulsive gambling |
| Learning disabilities |
| Asperger’s syndrome |
From the initial assessment, your treatment plan must address comorbid conditions (Table 1). This means taking a good history that includes corroborating information from relatives and data from the past, if possible. The case will then be much easier to manage, and quality of care greatly enhanced.
Stimulants: Usual first-choice therapy
In most cases, adult ADHD responds well to stimulant medications, although most available evidence is limited to studies in children. Several nonstimulant medications are also available, and the FDA is considering a new-drug application for a medication indicated for adult ADHD. Stimulants produce significant improvement in 30% of patients and mixed results in another 40%. Comorbidities may account for the 10 to 30% of patients who do not respond to stimulant therapy.
Methylphenidate, taken multiple times daily, is the most common treatment for ADHD. Dextroamphetamine and mixed salts of amphetamine also are used (Table 2).3 Patients usually respond to either methylphenidate or an amphetamine, and typically 25% of those who do not respond to one will respond to the other. When the clinical efficacy of amphetamines diminishes over time, many psychiatrists rotate medications. Replacing one amphetamine with another often eliminates the need to slowly increase the dosage and allows the clinician to maintain a relatively stable regimen.