This is true to an extent, I think the focus there (if done correctly) isn’t on being retributive so much as ensuring a very safe “err on the side of caution” buffer that often means longer times spent imprisoned than the exact point that they are rehabilitated.
I’m not 100% sure, that’s a good point, I’ll look into this. I agree in this case is does seem that way, but be careful for falling prey to making conclusions on a sample size of 1, there are outliers in any data sample. To be sure there are without doubt cases where the insanity plea yield shorter sentences, but from my education on the topic it’s always been my understanding that this is the case on average (to be clear, this isn’t through internet articles or word of mouth on Facebook, this was from multiple sociology and criminal psychology courses taught by PHd educated individuals. As a disclaimer while I have a Masters in Psychology and have done original research in political psychology, my main field is not criminal psychology specifically).
I looked for a solid while and couldn’t verify the claim of my past professors, I found one study in New Zealand contradicting this claim specifically saying that on average NGRI (not guilty by reason of insanity cases) served shorter sentences (note the wording of “served” referring to how much time they actually served, rather than just the sentence as you were asking about initially) on average in murder cases compared to other individuals with serious mental illness that did not receive NGRI sentences. However they take this as evidence (since it’s based on actual time served, rather than the initial sentence), that murder cases treated as NGRI are a positive vs. putting these same individuals in prison given the taxpayer pays for them to be incarcerated for a shorter period of time, AND alongside this results in a lower likelihood of future reoffending upon release. Some things I found across studies was 1) there is heavy racial and gender bias present in when NGRI pleas are granted, 2) recidivism rates are generally lower in NGRI cases upon release.
Thanks for raising this point, I learned some things!
Links below:
https://sci-hub.se/10.1002/cbm.2120
https://sci-hub.se/10.1016/j.fsiml.2020.100033