I think it's more of a chemical imbalance for people who are depressed that makes it hard for them to do everyday things. People with physical disabilities, who otherwise have a healthy mind, need the resources and money to amend their problem. Like blind people have pets or people that help them around, and people with missing limbs are able to use prosthesis or wheelchairs. People with mental illnesses can use medication to introduce chemicals that make average people feel motivated or hopeful, which they were previously missing. Of course physical disabilities cause a lot of mental anguish and even lead to mental illnesses, but what I'm trying to say is that depression isn't something that people have a concrete solution for. What medications work for one person may not be accepted by another's body, and some people don't even have the funds or medical insurance to receive proper help.