The standard insanity instruction is a perfect fit for murder, mayhem and crimes of violence. It is a lot less suited to cases involving a specified intent such as willful, fraudulent, “intent to defraud”. Also, the burden of proof for insanity may be on the defense. This can conflict with a burden of proof to establish an element of the offense that reflects that same intent. We have a modified 9th Circuit model insanity instruction with authorities. You can use this in cases where the same evidence used to prove insanity, would also tend to negate the mental state necessary for the offense itself.
6.4 INSANITY (Modified)
The defendant contends she was insane at the time of the crime. Insanity is a defense to the charge. The sanity of the defendant at the time of the crime charged is therefore a question you must decide.
A defendant is insane only if at the time of the crime charged:
1. The defendant had a severe mental disease or defect; and
2. As a result, the defendant was unable to appreciate the nature and quality or the wrongfulness of her acts.
The defendant has the burden of proving the defense of insanity by clear and convincing evidence. Clear and convincing evidence of insanity means that it is highly probable that the defendant was insane at the time of the crime. Proof by clear and convincing evidence is a lower standard of proof than proof beyond a reasonable doubt.
You may consider evidence of defendant’s mental condition before or after the crime to decide whether defendant was insane at the time of the crime. Insanity may be temporary or extended.
Your finding on the question of whether the defendant was insane at the time of the crime must be unanimous.
The same evidence offered to establish insanity may also be relevant to your determination of whether Vilasni Ganesh did or did not form the required criminal intent to commit the charged crimes. The government has the burden to prove beyond a reasonable doubt every fact necessary to constitute the crimes charged. You may consider all medical evidence to determine whether or not the government has met that burden.
[T]he Due Process Clause protects the accused against conviction except upon proof beyond a reasonable doubt of every fact necessary to constitute the crime with which he is charged.” In re Winship, 397 U.S. 358, 364 (1970) United States v. Leal–Cruz, 431 F.3d 667, 670–72 (9th Cir.2005), held that due process “forbids shifting the burden of proof to the defendant on an issue only where establishing the defense would necessarily negate an element that the prosecution must prove beyond a reasonable doubt under Winship.” Leal-Cruz at 671