Of Atkins and men: deviations from clinical definitions of mental retardation in death penalty cases.

Under Atkins v. Virginia, the Eighth Amendment exempts from execution individuals who meet the clinical definitions of mental retardation set forth by the American Association on Intellectual and Developmental Disabilities and the American Psychiatric Association. Both define mental retardation as significantly subaverage intellectual functioning accompanied by significant limitations in adaptive functioning, originating before the age of 18.