Intellectual disability

(24) “Intellectual disability” means significantly subaverage general intellectual functioning existing concurrently with deficits in adaptive behavior which manifests before the age of 18 and can reasonably be expected to continue indefinitely. For the purposes of this definition, the term:

(a) “Adaptive behavior” means the effectiveness or degree with which an individual meets the standards of personal independence and social responsibility expected of his or her age, cultural group, and community.
(b) “Significantly subaverage general intellectual functioning” means performance that is two or more standard deviations from the mean score on a standardized intelligence test specified in the rules of the agency.

For purposes of the application of the criminal laws and procedural rules of this state to matters relating to pretrial, trial, sentencing, and any matters relating to the imposition and execution of the death penalty, the terms “intellectual disability” or “intellectually disabled” are interchangeable with and have the same meaning as the terms “mental retardation” or “retardation” and “mentally retarded” as defined in this section before July 1, 2013.