Attention-deficit/hyperactivity disorder (ADHD) affects about one-third of adults who had ADHD in childhood. It can be difficult to diagnose because of the overlap in symptoms of adult ADHD with depression, anxiety and substance abuse, and reliance of the patient’s self report of symptoms. Studies of self-referral suggest that only 1/3 – ½ of adults who believe they have ADHD actually met formal diagnostic criteria. There are proponents of adult-onset ADHD, but one has to be cautious with the diagnosis because some adult patients self-report symptoms to gain access to stimulant medications. In fact, these other psychiatric conditions are more common in adults than ADHD. Also co-morbidity is the rule rather than the exception.
There is evidence that the diagnostic features of ADHD take a different form in adults compared to children. The DSM criteria are geared towards diagnosing ADHD in children. For example, adults with ADHD typically do not present with hyperactivity the way it is seen in children with ADHD. Instead they can present with restlessness, difficulty relaxing and a feeling of chronically being “on edge”. Impulsivity often takes on the form of socially inappropriate behavior. Inattention is commonly seen in adult ADHD, with symptoms of forgetfulness, disorganization, poor concentration, and difficulty prioritizing. In addition adults with ADHD and people around them report related mood symptoms, like mood lability and stress intolerance. Under the conditions of increased emotional arousal from external demands, the patient becomes more disorganized and distractible.
Wender developed a set of ADHD criteria, referred to as the Utah criteria, for diagnosing ADHD in adults:
- Childhood history consistent with ADHD (symptoms of inattention, hyperactivity, impulsivity starting before age 7 and causing impairment in two or more settings.
- Adult symptoms
- Hyperactivity and poor concentration
- Two of the following:
- Affective lability
- Hot temper
- Inability to complete tasks and disorganization
- Stress intolerance
Assessment for ADHD in adults should include: (1) obtaining a developmental history, to determine if symptoms were present since early childhood, including attempting to corroborate information with other sources, (2) inquiring about the impact of core ADHD symptoms on current occupational, school and relationship functioning, (3) having the patient perform screening tasks in the office setting to assess attention, concentration, distractibility and short-term memory, and (4) assessing for the presence of other psychiatric disorders and substance abuse. Self-report instruments, like the Wender Utah Rating Scale and the Brown Adult Attention Deficit Disorder Scale, can be useful for initial screening but should not be used alone to diagnose ADHD in an adult patient.
Here is a chart that can help with the Differential Diagnosis for ADHD in adults:
|Psychiatric disorder||Features shared with ADHD||Distinctive features|
|Major depression||Poor concentration, attention and memory, difficulty with task completion||Enduring dysphoric mood or anhedonia, sleep and appetite disturbance|
|Bipolar disorder||Hyperactivity, inattention, poor focus, mood swings||Enduring dysphoric or euphoric mood, insomnia, psychotic symptoms|
|Generalized anxiety||Fidgetiness, difficulty concentrating||Exaggerated apprehension and worry, somatic symptoms of anxiety|
|Substance abuse||Poor attention, concentration and memory; mood swings||Pattern of substance use with social, occupational and health consequences; tolerance and withdrawal|
|Personality disorders, particularly borderline PD and antisocial PD||Impulsivity, affective lability||Arrest history (ASPD), repeated self-injury or suicidal behavior (BPD); lack of recognition that behavior is self-defeating|
Adapted from Adult ADHD: Evaluation and Treatment in Family Medicine, AAFP, November 1, 2000, Table 5
Though it is rare, medical conditions that can mimic ADHD in adults include hyperthyroidism, petit and partial complex seizures, hearing deficits, hepatic disease, sleep apnea, head injury, and lead toxicity. If there are concerning findings on physical exam, then these should be pursued.
There are times when a diagnosis of ADHD is appropriate in an adult patient. When treating ADHD symptoms in an adult, consider non-stimulant approaches (Strattera, Intuniv, and Wellbutrin), and if prescribing a stimulant, avoid short-acting stimulants, which have a greater potential for addiction. Long acting formulations are less likely to be abusable.
Diagnosing and treating Attention Deficit Hyperactivity Disorder (ADHD) in adults is tricky. It is our hope that this primer helps primary care providers to determine the next steps when an adult patient comes in with a request for treatment for ADHD.
Reference: Adult ADHD: Evaluation and Treatment in Family Medicine; H. Russell Searight PhD et al; Am Fam Physician; November 1, 2000; 2077-2086