In Oregon, if you commit a felony, but have a mental condition that absolves you of criminal liability, you may be found guilty except for insanity.
Individuals who are found guilty except for insanity are committed to the state Psychiatric Review Board for the maximum possible sentence they could have received if convicted.
In short, those who are guilty except for insanity do not simply walk out of the courtroom. They are involuntarily committed to the Oregon Health Authority for as long a prison term as they could possibly be sentenced to by a judge.
For this reason, some people actually believe that it is better to take criminal punishment instead.
An example might be a schizophrenic person who breaks into a building and commits 1st class burglary. As an A felony, Burglary I is punishable by up to 20 years in prison. But it is not a measure 11 crime, so in certain circumstances, defendants might even not go to prison.
But if you are found guilty of burglary I except for insanity, you will be committed to the OHA for no less than 20 years.
Those who are committed to the state Psychiatric Review Board may get chances for release if they respond well to treatment and are able to understand their own actions and consequences. But they will always have a “hold” from the PRB until the maximum term is up. Since the obvious priority of the state is to minimize the risk to the public, involuntary commitment for many lower level crimes can end up being longer and more severe than ordinary criminal punishment.
As such, the defense of guilty except for insanity is typically sought only for the most serious cases, where defendants face long prison terms or even the death penalty.
You can read more about the Oregon Psychiatric Review Board here.