First of all you should understand that childhood depression is not a normal condition. Just because your child seems little nervous or sad, it doesn’t mean that they are in significant depression. But if the nervousness or sadness remain persistent and it affect their normal social activities, interests, schoolwork or family life then it definitely shows the indication of depressive illness. There are various signs and symptoms that will occur in your child behavior like irritability or anger, feelings of sadness and hopelessness, changes in appetite, changes in sleep, difficulty in concentrating, physical complaints and many more. In most cases, usually doctor does a thorough examination by asking specific questions and doing a physical examination test. Sometimes they ask for test which is performed in the laboratory by the help of tool that you can see at http://www.ilexmedical.com etc. It is usually for checking different medical conditions whether it is caused by depressive symptoms like anemia, thyroid, lack of calcium level and other hormonal problem too.