There’s no question that mental health issues can impair someone’s judgment and cause them to behave in unexpected ways – but is the “insanity defense” really viable?
Under California’s laws, you can’t be convicted of a crime if you were legally insane at the time of the offense, but meeting that legal definition can be more complicated than most people realize.
Insanity is very narrowly defined
In reality, an insanity defense is not used as often – nor as successfully – as popular media would make it seem. You can have mental health issues without being considered legally insane – especially in the context of a criminal case.
California uses what is called the “M’Naghten Rule” to establish whether someone can be held criminally liable for their actions. Insanity can be asserted when a defendant:
- Couldn’t understand the criminal nature of his or her actions, or
- Couldn’t distinguish right from wrong when they acted
It doesn’t matter if the defendant’s mental condition was temporary or ongoing, only that it existed at the time they committed their crime.
It’s important to understand, however, that insanity is an affirmative defense – which means the burden of proof is on the defendant. Using the insanity defense means admitting that you committed the crime – while still asserting that you shouldn’t be held criminally liable because of your mental state at the time. It’s also not permissible to use voluntary alcohol or drug intoxication as part of the defense or a basis for the insanity plea
