ADHD Evidence
In the beginning, the diagnosis of ADHD was unclear due to: l Different names l Inconsistent nature of impairments l Feedback from 3rd parties (ie, children are poor historians) l Media controversy l Lack of validated diagnostic instruments
But by 1998, the AMA called ADHD "…one of the best-researched disorders in medicine, and the overall data on its validity are far more compelling than for many medical conditions.”
Genetics l Numerous twin studies report the average heritability index to be approximately 0.75 across various sets of diagnostic criteria l Adoption and family studies further support the genetic basis for ADHD l Stressors and bad parenting can exacerbate impairment but do not cause ADHD
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