In the US criminal justice system, time served while incarcerated in a mental hospital can be much longer than what would have been the sentence without an insanity defence.

See: https://www.nytimes.com/2017/09/27/maga ... tence.html

I think in Canada it works about to be on average about the same either way. Also those deemed not criminally responsible and treated have lower recidivism rates than the rest of the inmate population.

The 25 years is likely to calm the public that no one is getting away with murder. It looks like the sentence requires 3 years before she can be let out for supervised release as part of her rehabilitation.

In principle I agree with the OP that a sentence to a mental hospital is problematic but sometimes there is no alternative. I would rather be in forensic hospital than in jail, but it is a tough place to be... much harder to cope with that a regular psych ward.