Depression is a thing of the mind; it attacks the mind and its effects evident externally. Hence, as individuals, we have the responsibility of controlling what goes on in our minds. Because what can take our minds can take our life.
Honestly, so many things are happening in the world, all around us that are capable of sending us into the 'cage' of depression (like you've made us understand in this post). But then, we must be very particular about what we think so that we don't get drained by depression-- the killer in disguise.
Thanks, @euronation for sharing.