§ 76-2-305. Mental illness -- Use as a defense -- Influence of alcohol or other substance voluntarily consumed -- Definition.

(1)

(a) It is a defense to a prosecution under any statute or ordinance that the defendant, as a result of mental illness, lacked the mental state required as an element of the offense charged.

(b) Mental illness is not otherwise a defense, but may be evidence in mitigation of the penalty in a capital felony under Section 76-3-207 and may be evidence of special mitigation reducing the level of a criminal homicide or attempted criminal homicide offense under Section 76-5-205.5.

(2) The defense defined in this section includes the defenses known as "insanity" and "diminished mental capacity."

(3) A person who asserts a defense of insanity or diminished mental capacity, and who is under the influence of voluntarily consumed, injected, or ingested alcohol, controlled substances, or volatile substances at the time of the alleged offense is not excused from criminal responsibility on the basis of mental illness if the alcohol or substance caused, triggered, or substantially contributed to the mental illness.

(4)

(a) "Mental illness" means a mental disease or defect that substantially impairs a person's mental, emotional, or behavioral functioning. A mental defect may be a congenital condition, the result of injury, or a residual effect of a physical or mental disease and includes, but is not limited to, mental retardation.

(b) "Mental illness" does not mean an abnormality manifested primarily by repeated criminal conduct.

(5) "Mental retardation" means a significant subaverage general intellectual functioning, existing concurrently with deficits in adaptive behavior, and manifested prior to age 22.

Amended by Chapter 11, 2003 General Session