Clinical meaning
The DSM-5-TR diagnostic criteria for ADHD require: (A) a persistent pattern of inattention and/or hyperactivity-impulsivity that interferes with functioning, with six or more symptoms from either the inattention or hyperactivity-impulsivity domain (five or more for adults age 17 and older) present for at least 6 months; (B) several symptoms present before age 12 years; (C) symptoms present in two or more settings (home, school, work, social); (D) clear evidence of functional impairment; (E) symptoms not better explained by another mental disorder. Inattention symptoms include difficulty sustaining attention, not seeming to listen, failing to follow through on tasks, organizational difficulties, avoidance of sustained mental effort, losing things, distractibility, and forgetfulness. Hyperactivity-impulsivity symptoms include fidgeting, leaving seat, running/climbing inappropriately, inability to engage quietly, being on the go/driven by a motor, excessive talking, blurting out answers, difficulty waiting turn, and interrupting. Presentation specifiers: predominantly inattentive (ADHD-PI), predominantly hyperactive-impulsive (ADHD-PH), or combined (ADHD-C). The clinician conducts comprehensive evaluation including developmental history, academic/occupational functioning, collateral informants, validated rating scales, mental status examination, and differential diagnosis (anxiety disorders, mood disorders, learning disabilities, autism spectrum disorder, trauma, sleep disorders, substance use, thyroid dysfunction). The clinician rules out medical mimics with appropriate screening labs (TSH, CBC) and screens for commonly comorbid conditions (anxiety in 25-50%, depression in 20-30%, oppositional defiant disorder in 40-60%, learning disabilities in 20-30%).