Actually i want to know that how can we prevent the person from being depressed and also tell me some measures which help in recovery of that person?
What do you mean by preventive measures? You mean preventive measures to keep this person from being depressed or measures to help them recover?
I'm not exactly sure what you mean.
You don't say what your relationship might be to this person or what you might be in a position to prevent. When it was my daughter suffering from depression and anxiety (20 yrs old) I made sure she saw a primary care doctor then a specialist, a therapist and a psychiatrist including driving her there and keeping track of her appointments. I followed their advice on what to do, in her case when it was bad I had to be with her 24 hours a day and take control of her medication and car keys. Now she's doing better and doesn't need that level of monitoring.