Depression, or unipolar affective disorder, is a mood disorder which affects about 10% of the population. Everyone experiences "highs" and "lows" in life, but people with mood disorders experience them with greater intensity and for longer periods of time than most people.

Depression becomes an illness, or clinical depression, when the feelings described below are severe, last for several weeks, and begin to interfere with one's work and social life:

• feeling worthless, helpless or hopeless,
• sleeping more or less than usual,
• eating more or less than usual,
• having difficulty concentrating or making decisions,
• loss of interest in taking part in activities,
• decreased sex drive,
• avoiding other people,
• overwhelming feelings of sadness or grief,
• feeling unreasonably guilty,
• loss of energy, feeling very tired,
• thoughts of death or suicide.

There is no one cause of depression; neither is it fully understood. The following factors may make some people more prone than others to react to a loss or failure with a clinical depression:

• specific, distressing life events,
• a biochemical imbalance in the brain,
• psychological factors, like a negative or pessimistic view of life.

There may also be a genetic link since people with a family history of depression are more likely to experience it. If you suspect you have Depression, see your family doctor. Treatment options include medication and/or therapy.

Excerpts from CMHA National web site - Depression