“Actions don’t become different retroactively because of how the person who did them felt at the time.”
“Felt”, I would agree with. However, the truth of “non compos mentis” insanity, is that there is little or no doubt even by a layman that someone is “not in command of their faculties”. And this *is* satisfactory to most people that during these times they have little or no control over themselves, so should not be held entirely to blame for their actions.
I could cite several very dramatic examples, such as advanced pernicious anemia, caused by the inability to absorb Vitamin B12. There are many cases where a frothing, incoherent maniac in a straight jacket, and tied to a bed, when given an injection of B12 would, within one minute, return to complete clarity, sanity, along with some confusion as to where they were, and why?
But in the final analysis, whether a person is permanently or just temporarily insane, they need professional evaluation to determine if there is any degree of mitigation for their actions in that mental state.
Have you heard of PMS?