Use a validated ADHD screening questionnaire
Review symptoms with a licensed mental health professional
Get a full clinical evaluation
Check symptoms from childhood and adulthood
Assess symptoms in more than one setting
Evaluate impact on work, school, and daily life
Rule out other causes such as anxiety, depression, sleep problems, thyroid issues, and substance use
Gather input from parents, partners, teachers, or employers if available
Review medical history and current medications
Consider neuropsychological testing if recommended
Follow DSM-5 criteria during assessment
Seek diagnosis from a psychiatrist, psychologist, neurologist, or primary care clinician trained in ADHD assessment