In short, yes – a defendant can claim “temporary insanity” as a defense. The terms of the temporary insanity defense are outlined in Wisconsin Statute 971.15(1):
“A person is not responsible for criminal conduct if at the time of such conduct as a result of mental disease or defect the person lacked substantial capacity either to appreciate the wrongfulness of his or her conduct or conform his or her conduct to the requirements of law.”
So the requirement is that the person had:
- a “mental disease or defect” (what we colloquially refer to “insanity”).
- “at the time of such conduct,” meaning the conduct for which the person has been charged criminally.
So for the purposes of an “insanity defense” it matters what a person’s mental state was at the time of the alleged conduct, not before, afterwards.
How to Plead?
The statute addresses only whether a person is “responsible” for criminal conduct. It doesn’t address guilt. So a person charged with a crime and for whom the above statute may apply still has to decide how to plead to the crime. A person can plead guilty or not guilty and still invoke 971.15(1) either way, as described in Wisconsin Statute 971.06(1)(d).
If a person pleaded not guilty and not guilty by reason of mental disease or defect, the court would then hold a “bifurcated” trial, meaning a trial with two parts (this procedure is spelled out in Wisconsin Statute 971.165). The first part of the trial would be the “guilt” phase, where the jury would decide whether the person was guilty of committing all of the elements of the alleged crime. If the jury finds the person not guilty, that is the end of the proceeding. If the jury finds the person guilty, then the court moves on to the second part of the “bifurcated” trial: determining whether the person is not legally responsible for what he did by reason of mental disease or defect. If a person joins a plea of guilty with a plea of not guilty by reason of mental disease or defect, he is admitting, in the language of Wisconsin Statute 971.06(1)(d), that “but for lack of mental capacity the defendant committed all the essential elements of the offense charge.” So a person could plead guilty, in effect admitting to the crime, but then join that plea with a plea of not guilty by reason of mental disease or defect, in effect saying that he was “temporarily insane” and thus should not be held criminally responsible for that conduct.
Health Services vs. Prison
If a person is found not guilty by reason of mental disease or defect of a felony, the court commits that person to the department of health services rather than sentencing them criminally. The court commits the person to the department of health services for a specified period of time that cannot be any longer than the maximum amount of time they could have been sentenced to prison for the felony in question had they been convicted.