Poverty linked to epigenetic changes and mental illness: https://www.nature.com/news/poverty-linked-to-epigenetic-cha...
Childhood poverty linked to brain changes related to depression: https://www.medicalnewstoday.com/news/childhood-poverty-link...
What Poverty Does to Your Brain: https://www.attn.com/stories/2442/effects-poverty-brain-ment...
What Poverty Does to the Young Brain: https://www.newyorker.com/tech/elements/what-poverty-does-to...
'Crack baby' study ends with unexpected but clear result: http://www.philly.com/philly/health/20130721__Crack_baby__st...
How Poverty Taxes the Brain: https://www.citylab.com/life/2013/08/how-poverty-taxes-brain...
Freeing Up Intelligence: https://scholar.harvard.edu/sendhil/publications/freeing-int...
Growing Up Poor Is Bad for Your Brain: https://motherboard.vice.com/en_us/article/vvb4gy/growing-up...
These articles should be pretty good reads on the subject. Let me know if any of them are especially weak.