Symptoms of depression vary from person to person, but often include feeling low, numb, worthless or without hope. You may find you sleep too much or too little, don’t eat properly, and withdraw from social contact with friends and family.There are lots of reasons why someone might feel depressed, but sometimes there isn’t any obvious reason. It can be caused by a difficult life event – losing a job, relationship difficulties, or physical health problems like illness and disability, or low self-esteem.