How do you determine if a 4 year old has adhd?

Not easily: A 4 yo definitely can have adhd, but many that age have similar behaviors that ease with time. Family history can be useful, as can the child's behavioral patterns up to that point. Usually, hyperactivity and impulsivity are the key features, with aggression and rule breaking the behaviors that call attention. Needs a thorough work-up by a professional experienced with assessing young children.

Testing : A four year old can be tested for adhd using questionnaire data, extensive personal & family history, physical examination, neurodevelopmental assessment and the peer (a test developed by mel levine, md, to assess cortical function in 4-6 year-olds.).