What causes emotional depression?

Most depression is caused, physiologically, by the inability for the body to produce a neurotransmitter in the brain called seratonin. There is medication that helps this condition. There are also non-medication approaches that can help minimize the effects of depression such as exercise, talking with a therapist or counselor, eating a healthy diet, staying away from drugs and alcohol, staying active with friends and hobbies, etc.

Many people think depression is hereditary. Most likely others in the family had / have depression, too. Some people are born predisposed to depression and traumatic events in childhood -- or even later, make depression worse.

The best cure is to treat it holistically. With your mind, spirit and body. Take care of yourself -- exercise, eat right, rest, surround yourself with positive, supportive people. Get therapy if you need it.

Stress, working too much, The death of a loved one, hating your job. I could go on. eating a poor diet....
For me, the thing that depresses me the most is that all the days are exactly the same, I do the same things at the same time everyday. Also, if you are a woman, hormones are a major cause of depression, women get depressed before their period, or if they are pregnant, or at menopause. A good means for overcoming depression is getting closer to god, go to church or a religious group, it really gives you strength knowing that god is there for you.
Lots of reasons....trauma, chemical imbalance in brain from something the body goes thru, stress, eating the wrong foods might have an affect, maybe even boredom...