(9) “Developmental disability” means a disability that: (a) is attributable to intellectual disability, cerebral palsy, epilepsy, autism, or any other neurologically disabling condition closely related to intellectual disability; (b) requires treatment similar to that required by intellectually disabled individuals; (c) originated before the individual attained age 18; (d) has continued or can be expected to continue indefinitely; and (e) results in the person having a substantial disability.
Citation: Mont. Code Ann. § 53-20-102 (West)