I think depression is a term used to describe a myriad of symptoms. Depression can be temporary, terminal, circumstantial, chemically induced or chronic and caused by brain disorders.
This is what makes it so illusive.
I believe most people have had or will experience suicidal ideation. Most will recognise the danger and take steps to prevent ideation from becoming a true death wish.
Those who allow themselves to fixate on death and remove the natural instinct for survival will at some time attempt to take their lives.
All children experience their world by exploration. Sometimes they get hurt but the laws of nature dictate that we learn not to do things that cause us pain. That is natural.
When we do things over and over even though these things cause us pain, something is wrong.
Mental disorders merit the same urgency that physical disorders do. The problem must be diagnosed and hopefully, treated. Some problems have no effective solution, but many more do.
We must remember that our love for another person cannot take the place of an anti-biotic when they have a virus, and our love cannot take the place of anti-depressants when they are in need of emotional relief, regardless of how the condition came into existance.