In all criminal cases in which the trial judge charges the jury on the law relating to the defense of insanity, the judge shall also charge the jury that, if it should find the defendant to be not guilty by reason of insanity, that it shall so state in its verdict.
Instructions concerning insanity
Tenn. Code Ann. § 40-18-117, under Trial and Verdict.
Tenn. Code Ann. § 40-18-117