Sadness like this will usually pass with time. Occasionally it will just drag on, or it may get worse and worse. On the other hand, unhappiness just comes 'out of the blue', for no obvious reason. If depression goes on and on, is severe, or dominates every part of someone's daily life, it should be treated as a medical illness. Certain symptoms can give a clue that someone is suffering from the kind of depression that will need help.
Someone suffering from depression can start to behave out of character, both at home and at work.
Unable to delegate tasks Working, or trying to work, much too hard Depression can seriously affect someone's ability to work effectively. It may be so bad that he or she will have to stop work completely for a time. When it is not quite that bad, most people will try to soldier on, painfully aware that they are not doing their job as well as they usually do. If someone's depression can be recognised and helped, they will get back much more quickly to their normal performance at work. Much needless unhappiness and suffering can be avoided.