Attention-deficit/hyperactivity disorder (ADHD) affects about 1/3 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 solely on the patient’s self report of symptoms. Studies of self-referral suggest that only 1/3-1/2 of adults who believe they have ADHD actually met formal diagnostic criteria. More commonly, the presenting symptoms are actually related to other psychiatric diagnoses, like depression, anxiety and substance abuse.
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 (and even adolescents) with ADHD typically do not present with hyperactivity the way that children with ADHD do. 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 conditions of increased emotional arousal from external demands, the individual can become 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 adults.
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 less commonly seen, some medical conditions can mimic ADHD in adults. These 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 evaluated further.
Once a provider is comfortable with a diagnosis of ADHD in an adult patient, then treatment can be discussed. Therapy to discuss organizational skills, optimizing concentration, and develop strategies to deal with restlessness can be helpful. Providers are often hesitant to consider medication treatment because of the concern of the addiction potential for stimulant medication. It is important to keep in mind that patients who truly have ADHD and are not being adequately treated are at higher risk for self-medicating with illicit drugs. When treating ADHD in an adult, a conservative approach would be to consider a non-stimulant approach first (Strattera, Intuniv, or Wellbutrin), and if prescribing a stimulant, to focus on extended-release preparations and to avoid short-acting stimulants, which have a greater addiction potential. And of course, contact us at PC2 for guidance on a particular case.
Reference: Adult ADHD: Evaluation and Treatment in Family Medicine; H. Russell Searight PhD et al; Am Fam Physician; November 1, 2000; 2077-2086