TL;DR: no change, like physical health, but more community focus is likely to improve outcomes.

I'm not exactly sure what you think would be different in solarpunk? The mental health continuum (like the physical) doesn't change. Different indeginous groups have differing mental health practices and histories, but like physical health best practices shouldn't be region dependant. This differences are primarily at healthy and pre-injury levels anyways (where I personally liked to see patient led decisions over imposed group decisions)

At the healthy end of things, solarpunk is more community based which creates more positive environments, but it's not something easy to quantify, and thus compare.

At the warn/pre-injury level, community focus makes more resilient people and groups, so there should be more self-recovery from this part of the scale. Hard to quantify as above. Some additional social work here can also improve self-recovery, but that's a resource question.

At injury, treatment is therapy supplimented with medications. When therapy resources are lacking other medical professionals lean on medication, but that's a resource question. No change.

At severe injury, management is therapy supplimented with medications; with patient freedoms restriction to pervent self or others harm. No change.