Perhaps you're familiar with The Doors' song People are Strange which neatly summarizes my experience with depression:

People are strange
When you're a stranger,
Faces look ugly
When you're alone,
Women seem wicked
When you're unwanted,
Streets are uneven
When you're down.

In the deepest parts of depression the isolation becomes complete. Even when someone makes the effort to reach out, you just cannot respond even to let them in. Most people don't make the effort, in fact they avoid you. It is common for strangers to cross the street to avoid coming close to a depressed person.

Depression may lead to thoughts of suicide or obsessive thoughts of death in general. I have known depressed people to tell me in all seriousness that I would be better off if they were gone. There can be suicide attempts. Sometimes the attempts are successful.

One in five untreated manic depressives ends their lives at their own hands. There is much better hope for those who seek treatment, but unfortunately most manic depressives are never treated - it is estimated that only one third of those who are depressed ever get treatment. In all too many cases the diagnosis of mental illness is made post-mortem based on the memories of grieving friends and relatives.

If you come across a depressed person as you go about your day, one of the kindest things you can do for them is to walk right up, look them straight in the eye, and just say hello. One of the worst parts of being depressed is the unwillingness that others have to even acknowledge that I'm a member of the human race.

On the other hand, a manic-depressive friend who reviewed my drafts had this to say:

When I am depressed I don't want the company of strangers, and often not even the company of many friends. I wouldn't go as far as to say I "like" being alone, but the obligation to relate to another person in some way is loathsome. I also become more irritable sometimes and find the usual ritual pleasantries unbearable. I only want interaction with people with whom I can really connect, and for the most part I don't feel like anyone can connect with me at that point. I begin to feel like some subspecies of humankind and as such I feel repulsive and repulsed. I feel like people around me can literally see my depression as if it were some grotesque wart on my face. I just want to hide and drop into the shadows. For some reason, I find it a problem that people seem to want to talk to me wherever I go. I must give out some kind of vibe that I am approachable. When depressed my low profile and head-hanging demeanor is really meant to discourage people from approaching me.

Thus it is important to respect each individual, for the depressed as for everyone else.

next: Effectiveness of Antidepressants