A 28-year-old woman presents with complaints of anxiety and mild depression. She says, "I am anxious about many things, and I feel sad sometimes." She is married and has recently returned to work as a meeting planner after taking several years off following the birth of her daughter. Following a consultation, physical examination, psychiatric history, and mental status examination, she is diagnosed with generalized anxiety disorder and a selective serotonin reuptake inhibitor (SSRI) is prescribed. Forgetting both the follow-up and then the rescheduled appointment, she says she is compliant with her medication and reports a modest reduction in her anxiety symptoms.

Nine months after the patient's generalized anxiety disorder diagnosis, she returns complaining of increasing difficulties with concentration and focus and a general feeling of nervousness. She has been placed on probation at work for failing to meet deadlines, not keeping assigned hours, misplacing important documents, constantly interrupting coworkers, and repeatedly making careless mistakes. She admits finding it difficult to begin tasks and often leaves them to the last minute. She says that her mind is "always wandering." At home, she finds herself unable to keep up with housekeeping, manage parenting responsibilities and household finances, and she feels overwhelmed by the demands placed on her. She notes that she is easily distracted from whatever task she is performing. She admits to drinking one glass of wine in the evenings and using nicotine because she finds it difficult to relax, but she denies substance abuse. The clinical interview is complicated by the patient's frequent interruptions and excessive talkativeness; fidgeting is also observed. No physical cause for her symptoms has been identified. The Adult ADHD Self-Report Scale Symptom Checklist is administered. 'Her score is 19. Patients with scores of 17-23 are likely to have attention-deficit/hyperactivity disorder (ADHD), and those who score ≥ 24 are highly likely to have ADHD.