Notwithstanding § 2-7-35, "handicap" and "handicapped" as used in this article mean a substantial physical or mental impairment, whether congenital or acquired by accident, injury, or disease, where the impairment is verified by medical findings and appears reasonably certain to continue throughout the lifetime of the individual without substantial improvement. This does not include an individual who is an alcohol, drug, narcotic, or other substance abuser or who is only regarded as being handicapped. The term "mental impairment" does not include mental illness.