Is insanity a justification defense

In the US, temporary insanity or permanent insanity is a defense when a person commits a crime. The reasoning is logical. Persons mentally ill very often have no idea what they are doing if they strike someone on the street for no cause. Clearly this person is too mentally impaired to obey laws and medical help rather than jail is required. Also, there is a defense called temporary insanity. In this situation, if a person has anger problems and reacts to a situation that brings them into a rage, the offense may be excused or if convicted, the person may be charged with a lesser crime. Here' s an example. If a husband comes home to find his wife in bed with another man, the rage might cause the intruding man to be seriously assaulted by the husband who can be said to be temporarily insane.