I work with people experiencing homelessness, and I've worked inpatient psych where I saw the full gamut of socioeconomic statuses, and can confidently tell you people who attribute their depression to external factors that are out of their control universally fail in treatment. There are a ton of people on the street who aren't depressed, and a bunch of rich people who want for nothing who are depressed. Sometimes, depression is caused by a neurotransmitter issue and meds work, but more often the issue is a pattern of thinking and perception, and the only treatment is learning new ways to think.