Short-term trials involving adults with ADHD have shown significant improvements in symptoms with stimulants and atomoxetine; however, data on long-term benefits and risks of these medications, particularly among older persons, have been insufficient. The latest article in our Clinical Practice series looks at this topic.
ADHD is characterized by symptoms of impulsivity, inattention, and hyperactivity that emerge in childhood. ADHD was initially considered to be solely a childhood disorder, and the diagnosis of adult ADHD was controversial. However, long-term follow-up studies revealed that in 40 to 60% of children with ADHD, the disorder persists into adulthood.
• How does the presentation of ADHD differ in adults as compared to children?
The presentation of ADHD in adults is different from that in children, in part because of a greater decrease in symptoms of hyperactivity than in symptoms of inattention. Also, impairment manifests in different settings in adulthood than in childhood. In the transition of ADHD from childhood to adulthood, the declining symptoms of hyperactivity may present as restlessness, whereas the persisting inattentive symptoms may manifest in various tasks (e.g., difficulties being organized, keeping appointments, meeting deadlines, or focusing on a single task) and affect important life functions in multiple settings. Consequences of ADHD in adulthood include difficulties professionally (e.g., frequent job changes, unemployment, and lower socioeconomic status), personally (social maladjustment, high rates of separation and divorce), and clinically (comorbid psychiatric disorders like depression and anxiety). There is also an increased risk for substance abuse, including smoking.
• What nongenetic factors have been associated with ADHD?
Nongenetic factors have also been associated with ADHD. Observational studies have shown 2- to 3-fold increased risks of ADHD among offspring of mothers who smoked during pregnancy and in those with evidence of lead exposure in childhood. Persons with obesity or diabetes and those whose mothers had these conditions in pregnancy have also been reported to have greater risk of ADHD. It is not known whether these associations are causal.
Morning Report Questions
Q: What are the DSM-5 criteria for diagnosis of adult ADHD?
A: The DSM-5 diagnosis in adults is based on having at least five of nine symptoms in two domains — inattention, and hyperactivity and impulsivity. In DSM-5, the previous distinction of “subtypes” (predominance of inattentive symptoms, hyperactive and impulsive symptoms, or both types of symptoms) was changed to indicate “presentations at the time of assessment,” reflecting the developmental instability of ADHD symptoms. This cutoff for number of symptoms applies to both adults and children. The age at which symptoms began, which previously was before age 7, was increased to before age 12. For adults not diagnosed in childhood, this criterion requires a retrospective report of childhood ADHD, which may not be accurate. Self-report of current symptoms in adults can also be problematic, as it is less predictive than reports from others regarding problems with employment (job dismissals and lack of promotions), domestic life (strained relationships with spouse and children or divorce), and social activities (friendship breakups). Because of this, DSM-5 recommends obtaining information from a significant other with long-term knowledge of the patient (e.g., friend or family member).
Q: What is the most effective treatment of adult ADHD?
A: Amphetamine-type stimulants (amphetamine and methylphenidate) are the most effective medications for the treatment of adult ADHD. In controlled studies, most adults with ADHD respond to either methylphenidate or amphetamine, so there is no recommendation to start with one versus the other. Approximately 70% of adults with ADHD show immediate improvements in attentiveness and reduced distractibility, with moderate to large effect sizes; effects are seen within 1 hour after administration (both for immediate-release and controlled-release formulations). Controlled-release formulations with a duration of efficacy of 6 to 10 hours might result in higher compliance than immediate-release formulations since they typically require only once-a-day dosing (maximal two doses), but data comparing adherence between them are lacking. Clinical studies reveal significant variation across individuals in the optimal dose of stimulant medication, and titration is necessary to optimize control of symptoms while minimizing adverse effects. Methylphenidate and amphetamine have similar adverse effects. These include insomnia, dry mouth, decreased appetite, weight loss, headaches, depression, and anxiety. Some patients tolerate one of these agents better than the other, and thus it is reasonable to try the alternative if side effects limit use of the initial agent.