Phillip Ruppert, PhD Assistant Professor Department of Psychiatry and Behavioral Neuroscience
Noam Grysman, MD Department of Psychiatry and Behavioral Neuroscience
George Grossberg, MD Samuel W. Fordyce Professor Director, Geriatric Psychiatry
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Saint Louis University School of Medicine St. Louis, Missouri
Disclosures The authors report no financial relationships with any companies whose products are mentioned in this article, or with manufacturers of competing products.
It can be particularly perplexing to diagnose ADHD in older adults because the other possible causes of the symptoms are vast. During the interview, it is important to ask questions that may rule out other psychiatric, neurologic, and medical conditions.21 Screen for other diagnoses, and include questions about a patient’s sleep history to rule out obstructive sleep apnea.21 To screen for other psychiatric conditions, the Mini International Neuropsychiatric Interview 5.0.0 may be used.22 Other tools include the Saint Louis University AMSAD screen for depression, the Geriatric Depression Scale, and the Beck Anxiety Inventory.28,41 To screen for cognitive functioning, the Saint Louis University Mental Status Exam, Montreal Cognitive Assessment, or Mini-Mental State Examination can be used.22,28,42,43 Once screening is performed, a physical and neurologic examination is the best next step.26 Additionally, laboratory data and imaging can rule out other conditions; however, these are not routinely performed to diagnose ADHD.
Laboratory tests should include a comprehensive metabolic panel, complete blood count, thyroid-stimulating hormone level, B12/folate level, and possibly a vitamin D level.11,36 These tests cover several conditions that may mimic ADHD. Brain MRI is not routinely recommended for diagnosing ADHD, though it may be useful because some research has found brain structural differences in individuals with ADHD.28,44,45 Neurocognitive disorders have notable MRI findings that distinguish them from ADHD and each other.24 If there is significant concern for neurocognitive disorders, more specific tests can be employed, such as CSF studies, to look for phosphorylated tau and beta amyloid markers.11
Ask about family history (first-degree relative with ADHD) and obtain collateral information to make sure no other diagnoses are overlooked. Family history can help diagnose this disorder in older adults because there is evidence that ADHD runs in families.2,25 This evidence would ideally come from someone who has known the patient their entire life, such as a sibling or parent.24 The collateral information will be especially helpful to discern the chronicity of the patient’s symptoms, which would point toward a diagnosis of ADHD. To summarize (Figure 2):
obtain a thorough interview that may be supported by a screening tool
rule out other conditions
conduct a physical examination
obtain laboratory results
collect collateral information
obtain neuroimaging if necessary.
Treatment
ADHD symptoms can be treated with medications and psychotherapy. Research has shown the efficacy of ADHD medications in older adults, demonstrating that treatment leads to better functioning in multiple settings and decreases the risk for developing comorbid psychiatric conditions (mood disorder, substance use disorders).25,27 Symptoms that improve with medication include attention, concentration, self-efficacy, functioning, self-esteem, psychomotor agitation, mood, energy, and procrastination.21,31,46 If a patient with ADHD also has other psychiatric diagnoses, treat the most impairing disorder first.22 This often means mood disorders and substance use disorders must be remedied before ADHD is treated.21
Medication options include stimulants and nonstimulants. First-line treatments are stimulant medications, including methylphenidate, amphetamines, and mixed amphetamine salts.12,22,27,31,35 Stimulants have shown significant efficacy in older adults, although the American Geriatrics Society’s Beers Criteria list stimulants as potentially inappropriate for older adults.33 Adults show significant improvement with methylphenidate.21,23,47 In an observational study, Michielsen et al46 found stimulants were safe and efficacious in older adults if patients are carefully monitored for adverse effects, especially cardiovascular changes. Second-line treatments include the nonstimulant atomoxetine.12,22,27,31 Clonidine and guanfacine are FDA-approved for treating ADHD in children, but not approved for adults.26 There is little evidence for other treatments, such as bupropion.12,22,27 All of these medications have adverse effects, which are especially important to consider in older adults, who experience age-related physiological changes.
