Mine is caused by other issues mainly, and harsh bullying in my childhood that royally fucked me up. Plus with the current events going on, and the worsening weather, the knowledge such horrific "people" exist and were worshipped (cliff Richard, Rolf Harris, Jimmy saville), that we're on the brink of a third world and second cold war, that we're headed into an environmental doomsday that corporations wilfully are ensuring happens, and that the world is populated primarily with dicks, some of which start elaboratively claused and extended sentences so long and unnecessary indeed that they forget where one clause began and another ends and don't know even if the sentence makes sense, life's just, generally, cunk.
Meds turned me into a creationless zombie. The other meds I need are ringfenced by a system that almost seems purposefully geared against people with anxiety or depression. That and the lovely people of the world are very vocal about my problems to the extent that even my best friends talk about stabbing such folk if they ever met one.
I also think, though I am not talking about anybody in this thread, that people confuse depression with being depressed once in a while. If you can come out and say "I get depressed, but I deal with it" then you haven't faced the same thing at all. If you can cope with it it's not the same thing, everyone gets ups and downs, but not to the extent that people with depression struggle with.