Depression comes from mentally spending too much time in the past. Anxiety comes from mentally spending too much time in the future. Being present is the only way one can become aware of their inner happiness to counter the drag of day-to-day life.
Having no money can certainly exasperate depression but mainly people who are broke are living with past regret. About how they squandered their opportunities, money and time on things which ultimately left them where they are now. The potential of "What if?" eats away at their souls as they live a mundane existence just to survive.
RE: No one talks about how severe Money depression is.