Some of the most common conditions we see mistaken for ADHD are MDD, generalized anxiety disorder (GAD), and BD. In DSM-5-TR, 1 of the diagnostic criteria for MDD is “diminished ability to think or concentrate, or indecisiveness, nearly every day (either by subjective account or as observed by others).”41 Similarly, criteria for GAD include “difficulty concentrating.”42 DSM-5-TR also includes distractibility as one of the criteria for mania/hypomania. Table 420-22,41,42 lists other psychiatric, substance-related, medical, and environmental conditions that can produce ADHD-like symptoms. Referring to some medical and environmental explanations for inattention, Aiken22 pointed out, “Patients who suffer from these problems might ask their doctor for a stimulant, but none of those syndromes require a psychopharmacologic approach.” ADHD can be comorbid with other psychiatric conditions, so the presence of another psychiatric illness does not automatically rule out ADHD. If alternative psychiatric diagnoses have been identified, these can be discussed with the patient and treatment offered that targets the specified condition.
Once alternative explanations have been ruled out, focus on the patient’s developmental history. DSM-5-TR conceptualizes ADHD as a neurodevelopmental disorder, meaning it is expected to emerge early in life. Whereas previous editions of DSM specified that ADHD symptoms must be present before age 7, DSM-5 modified this age threshold to before age 12.1 This necessitates taking a careful life history in order to understand the presence or absence of symptoms at earlier developmental stages.5 ADHD should be verified by symptoms apparent in childhood and present across the lifespan.15
While this retrospective history is necessary, histories that rely on self-report alone are often unreliable. Collateral sources of information are generally more reliable when assessing for ADHD symptoms.13 Third-party sources can help confirm that any impairment is best attributed to ADHD rather than to another condition.15 Unfortunately, the difficulty of obtaining collateral information means it is often neglected, even in the literature.10 A parent is the ideal informant for gathering collateral information regarding a patient’s functioning in childhood.5 Suggested best practices also include obtaining collateral information from interviews with significant others, behavioral questionnaires completed by parents (for current and childhood symptoms), review of school records, and consideration of intellectual and achievement testing.43 If psychological testing is pursued, include validity testing to detect feigned symptoms.18,44
When evaluating for ADHD, assess not only for the presence of symptoms, but also if these symptoms produce significant functional impairment.13,15 Impairments in daily functioning can include impaired school participation, social participation, quality of relationships, family conflict, family activities, family functioning, and emotional functioning.45 Some symptoms may affect functioning in an adult’s life differently than they did during childhood, from missed work appointments to being late picking up kids from school. Research has shown that the correlation between the number of symptoms and functional impairment is weak, which means someone could experience all of the symptoms of ADHD without experiencing functional impairment.45 To make an accurate diagnosis, it is therefore important to clearly establish both the number of symptoms the patient is experiencing and whether these symptoms are clearly linked to functional impairments.10
Sensible treatment
Once a diagnosis of ADHD has been clearly established, clinicians need to consider how best to treat the condition (Table 5). Stimulants are generally considered first-line treatment for ADHD. In randomized clinical trials, they showed significant efficacy; for example, one study of 146 adults with ADHD found a 76% improvement with methylphenidate compared to 19% for the placebo group.46 Before starting a stimulant, certain comorbidities should be ruled out. If a patient has glaucoma or pheochromocytoma, they may first need treatment from or clearance by other specialists. Stimulants should likely be held in patients with hypertension, angina, or cardiovascular defects until receiving medical clearance. The risks of stimulants need to be discussed with female patients of childbearing age, weighing the benefits of treatment against the risks of medication use should the patient get pregnant. Patients with comorbid psychosis or uncontrolled bipolar illness should not receive stimulants due to the risk of exacerbation. Patients with active substance use disorders (SUDs) are generally not good candidates for stimulants because of the risk of misusing or diverting stimulants and the possibility that substance abuse may be causing their inattentive symptoms. Patients whose SUDs are in remission may cautiously be considered as candidates for stimulants. If patients misuse their prescribed stimulants, they should be switched to a nonstimulant medication such as atomoxetine, bupropion, guanfacine, or clonidine.47
Continue to: Once a patient is deemed...