Depression may also be melancholy: it may be discouragement, disappointment, abandonment, sadness, sorrow, mourning, rejection, regret, anxiety, grief, obsession, introspection, loss, separation, loneliness, isolation, alienation, guilt, loss of hope, temperamental woe and simple, pure, unhappiness.
It can be forms of low mood now out of date. The Edwardians were very keen on a condition known as "neurasthenia"; Virginia Woolf was diagnosed with it.
Fonte: BBC News - Not depressed, just sad, lonely or unhappy
