Can't comment on how it works in Canada but over here it's very difficult to prove insanity, and while it may keep someone out of jail, it'll get them locked up in a mental ward instead, which isn't exactly super happy fun time either.
Of course, there's also temporary insanity and from there we get into automatism, which looking at the quote was probably what he pleaded. Strangled your wife while you were sleepwalking? It's OK, you didn't know what you were doing. Have a cookie.![]()