Cardinal signs of depression are: fatigue, back and neck pain, headaches, loss of appetite, binge eating and worse case scenarios include suicidal thoughts.

Depression causes are vast. It can be brought on by stress, improper food intake, allergies and sugar. Lack of sunlight in the winter months can also trigger depression. Research has shown that two hours of a.m. sun is great towards alleviating depression.
Consult a qualified physician if depression is effecting your life.