La. Code Crim. Proc. art. 651
Current with operative changes from the 2024 Third Special Legislative Session
When a defendant is tried upon a plea of "not guilty", evidence of insanity or mental defect at the time of the offense shall not be admissible.
The defenses available under a combined plea of "not guilty and not guilty by reason of insanity" shall be tried together.
La. Cr.P. § 651