I can vouch for this. Money is not sufficient, and it might not be strictly necessary, but it's a huge lever.
Link: https://www.dn.se/nyheter/sverige/studie-psykisk-ohalsa-blir...
(only in Swedish, sorry!)
Here is the complete report (in Swedish): http://ltblekinge.se/globalassets/forskning-och-utveckling/b...
They mention a smiliar study from the US, but here money was only one out of multiple factors:
https://www.researchgate.net/publication/229888823_Supported...