Although there are certain 'core' symptoms of depression the precise way in which people suffer from the condition can vary from individual to individual. A study of 4,856 people with depression in Virginia, U.S. looked at their symptoms and the bad things that had happened to them over a period of 12 years and found that different negative events were associated with different symptoms. Deaths of loved ones and break-ups of relationships were both associated with high levels of sadness, anhedonia (lack of pleasure) and appetite loss and romantic break-ups were also associated with guilt. Chronic stress and failures were associated more with fatigue and sleepiness. Those who felt that no adverse event had caused their depression were more likely to suffer from fatigue, weight gain and thoughts of self-harm. Different individuals who had experienced the same events tended to suffer from similar symptoms while people who had suffered from a variety of negative experiences tended to suffer from different symptoms depending on what had gone wrong in their life.
Keller, Matthew C., Neale, Michael C. and Kendler, Kenneth S. - Association of different adverse life events with distinct patterns of depressive symptoms American Journal of Psychiatry October 2007, 164(10), 1521-1529