ADHD. To diagnose adhd, your doctor might use vandrtbiilt questionnaires for both parents and teachers. Based on those questionnaire, your physician might make the diagnosis or refer you to a psychologist to see if any comprbidity like depression, ocd.
A good interview. The evaluation of adhd is primarily done by a comprehensive interview in which questions are asked about the symptoms present and their effect on the person's life. The interviewer should ask family and/or friends to corroborate the symptoms and should rule out other possible reasons for the symptoms. Questionnaires and/ or psychological tests are also used to confirm the diagnosis.