Here's a bit more about what clinical depression is and what it isn't, along with the forms it can take, how it can be treated, and how it can affect family and friends of the depressed person.
Clinical depression is any of a group of illnesses called mood disorders.
A profound, acute depressed episode lasting two weeks or longer. A person's mood can be so depressed, and he or she can be so debilitated, as not to be able to work or even go out at all. The simplest of tasks may be impossible for him or her. It can bring on the desire to injure oneself or even cause thoughts of suicide . Major depressive episodes usually have a finite duration, lasting from several weeks to several months.