Attention-Deficit/Hyperactivity Disorder

ADHD is recognized by a pattern, not by one distracted visit. A child may sustain attention during a preferred one-to-one activity yet lose instructions, abandon multistep tasks, and interrupt peers across school and home. The diagnostic question is whether a persistent developmental pattern causes impairment in more than one setting—not whether the person can ever concentrate. The executive-control difficulty helps explain this uneven picture: attention, inhibition, working memory, and self-regulation are less reliably recruited, particularly when a task is lengthy, uninteresting, or poorly structured. That pattern is compatible with ADHD but is not specific to it; anxiety, depression, trauma, learning difficulty, sleep disruption, autism, substance use, and medical conditions can look similar. In Canada, diagnosis is clinical and criterion-based. Rating scales organize information from different observers but do not replace developmental history, functional assessment, examination, and differential diagnosis. CADDRA provides cross-lifespan guidance, while an NP’s authority to prescribe a controlled stimulant depends on federal and provincial or territorial requirements.