We all have been encountered with the depression in our life sooner or later. Children are more resistent to depression than others because they know how to live and be happy in the present moment. They do not worry too much about their past or future. They have always their minds open and always welcome new ideas, people , events without any pre-conditioned beliefs or principles attached to it. But as we grow up, our parents, elders, society start to condition our minds according to their beilefs and systems. If we argue with them, they tell us it is against their religion or civic norms, so we accept it and start becoming like data feeding machines who never ask for any logics and perform the tasks as given by the operators. 
Now comes the situation when we are failed in any specific mission or achievement, although we tried our best to it but could not succeed. In this way either we stand once again and start preparing with more energy and enthusisasm. But some people who only fail for one time, they start cursing their luck and go into depression, they doubt their capabilities and believe they cannot achieve success. They start living the life in depression. They cut theirselves from the society, friends, relatives because they all will ask them about the failure and they have no courage to tell them the exact reason.
It is really a major issue and most of the people even don't accept that they have depressions. With the proper examination and the help of psychologists this can be cured. Depression is a disease like any other diseases, firstly we have to believe it , then we can cure it. If we do not take it as any disease, we will not be able to find any mediaction about it. Happy mood hormones will be stimulated by different activites into their minds and body by different exercise and medicines.