Obviously, no one has all these signs. These are problems that tend to be associated with being sad. Yet, a depressed person may have only one, two or three of these signs. Sometimes it is called endogenous depression because it seems to come from within and not a reaction to external events. It affects sleep, appetite, energy level, self-esteem, and thoughts of suicide often occur.
Psychiatrists call it dysthymia or chronic sadness if the blue mood lasts for two years or more.
After a while, many do not know why they are down in the dumps. The bipolar types are just as likely to be men as women, more extroverted, and more likely to have relatives with depression. Secondly, the symptoms found and the judgment of how serious the symptoms are, vary according to who is making the diagnosis and how it is being made. For instance, the judgment that a particular person is depressed might be made by a therapist, family doctor, friend, spouse, psychological tester, or by self-evaluation. Sometimes even the psychological tests don't agree with each other.