Insanity

A. Not Guilty by Insanity

One may avoid liability for criminal acts by asserting that he or she was insane at the time of the crime.

1. Fairness
It is unfair to punish people for acts that result from mental illness.

2. No Deterrence
Punishing insane people does not have a deterrent effect, as it is difficult to deter acts resulting from mental illness.

B. Standards to Determine Insanity

Different jurisdictions employ different tests for determining if a defendant is legally insane.

1. The M’naghten Test
Under the M’naghten test, to establish a valid insanity defense, one must prove that due to mental illness, one:

a. Did not know the nature and quality of the act, or,

b. If one did know the nature and quality of the act, one still did not know the act was wrong.